National Library of Energy BETA

Sample records for arcs atomic-scale dynamics

  1. Atomic-scale investigations of the struct. and dynamics of complex catalytic materials

    SciTech Connect (OSTI)

    Karl Sohlberg, Drexel University

    2007-05-16

    By some accounts, catalysis impacts ? 30% of GDP in developed countries [Maxwell, I. E. Nature 394, 325-326 (1998)]. Catalysis is the enabling technology for petroleum production, for control of gaseous emissions from petroleum combustion, and for the production of industrial and consumer chemicals. Future applications of catalysis are potentially even more far reaching. There is an ever-growing need to move the economy from a fossil-fuel energy base to cleaner alternatives. Hydrogen-based combustion systems and fuel cells could play a dominant role, given a plentiful and inexpensive source of hydrogen. Photocatalysis is the most promising clean technology for hydrogen production, relying solely on water and sunlight, but performance enhancements in photocatalysis are needed to make this technology economically competitive. Given the enormously wide spread utilization of catalysts, even incremental performance enhancements would have far-reaching benefits for multiple end-use sectors. In the area of fuel and chemical production, such improvements would translate into vast reductions in energy consumption. At the consumption end, improvements in the catalysts involved would yield tremendous reductions in pollution. In the area of photocatalysis, such efficiency improvements could finally render hydrogen an economically viable fuel. Prerequisite to the non-empirical design and refinement of improved catalysts is the identification of the atomic-scale structure and properties of the catalytically active sites. This has become a major industrial research priority. The focus of this research program was to combine atomic-resolution Z-contrast electron microscopy with first-principles density functional theory calculations to deliver an atomic-scale description of heterogeneous catalytic systems that could form the basis for non-empirical design of improved catalysts with greater energy efficiency.

  2. Received 10 Apr 2013 | Accepted 22 Jul 2013 | Published 15 Aug 2013 Atomic-scale dynamic process of

    E-Print Network [OSTI]

    Zhu, Ting

    of partial dislocations in gold nanocrystals. The complete atomic-scale processes of nucleation, migration undergo migration and annihilation due to mechanical loading in a manner that is not expected in bulk, Atlanta, Georgia 30332, USA. 3 8915 Hampton Avenue NE, Albuquerque, New Mexico 87122, USA. 4 Department

  3. A Dynamic Traveling Salesman Problem with Stochastic Arc Costs

    E-Print Network [OSTI]

    Alejandro Toriello

    2012-08-31

    Aug 31, 2012 ... Abstract: We propose a dynamic traveling salesman problem (TSP) with stochastic arc costs motivated by applications, such as dynamic ...

  4. Dynamic Behaviors of Plasma Reflection during Keyhole Arc Welding

    E-Print Network [OSTI]

    Zhang, YuMing

    Dynamic Behaviors of Plasma Reflection during Keyhole Arc Welding YuMing Zhang and Yi Ma Welding Engineering College of Engineering University of Kentucky #12;Keyhole Double-Sided Arc Welding Work PAW Torch: in any existing arc welding process? No ! Why Not in Keyhole PAW? No current through the keyhole ! Plasma

  5. Arc$c Climate Dynamics James Overland

    E-Print Network [OSTI]

    · Carbon Chemistry- Mathis, Evans, Cross · Pacific Ecosystems- Stabeno, Moore, Mordy than in other regions of the globe (Arc%c Amplifica%on) Arc partnerships Contributed to wri$ng of the NOAA Arc%c Vision and Strategy Plan Part

  6. Atomic Scale Details of Defect-Boundary Interactions 

    E-Print Network [OSTI]

    Chen, Di

    2014-12-18

    The study is aimed to understand atomic scale details of defect-boundary interactions, which are critical to develop radiation tolerant fuel cladding materials for harsher neutron environments. By means of molecular dynamics simulations, we...

  7. Dynamic Resource Allocation with the arcControlTower

    E-Print Network [OSTI]

    Filipcic, Andrej; The ATLAS collaboration; Nilsen, Jon Kerr

    2015-01-01

    Distributed computing resources available for high-energy physics research are becoming less dedicated to one type of workflow and researchers’ workloads are increasingly exploiting modern computing technologies such as parallelism. The current pilot job management model used by many experiments relies on static dedicated resources and cannot easily adapt to these changes. The model used for ATLAS in Nordic countries and some other places enables a flexible job management system based on dynamic resources allocation. Rather than a fixed set of resources managed centrally, the model allows resources to be requested on the fly. The ARC Computing Element (ARC-CE) and ARC Control Tower (aCT) are the key components of the model. The aCT requests jobs from the ATLAS job management system (PanDA) and submits a fully-formed job description to ARC-CEs. ARC-CE can then dynamically request the required resources from the underlying batch system. In this paper we describe the architecture of the model and the experienc...

  8. CHEP2015: Dynamic Resource Allocation with arcControlTower

    E-Print Network [OSTI]

    Filipcic, Andrej; The ATLAS collaboration; Nilsen, Jon Kerr

    2015-01-01

    Distributed computing resources available for high-energy physics research are becoming less dedicated to one type of workflow and researchers’ workloads are increasingly exploiting modern computing technologies such as parallelism. The current pilot job management model used by many experiments relies on static dedicated resources and cannot easily adapt to these changes. The model used for ATLAS in Nordic countries and some other places enables a flexible job management system based on dynamic resources allocation. Rather than a fixed set of resources managed centrally, the model allows resources to be requested on the fly. The ARC Computing Element (ARC-CE) and ARC Control Tower (aCT) are the key components of the model. The aCT requests jobs from the ATLAS job mangement system (Panda) and submits a fully-formed job description to ARC-CEs. ARC-CE can then dynamically request the required resources from the underlying batch system. In this paper we describe the architecture of the model and the experience...

  9. Atomic scale heating in energetic plasma deposition

    E-Print Network [OSTI]

    Anders, Andre

    2001-01-01

    equation (2), for cathodic arc plasmas. The kinetic energiesscale heating in cathodic arc plasma deposition André Andersscale heating in cathodic arc plasma deposition André Anders

  10. Dynamic voltage-current characteristics for a water jet plasma arc

    SciTech Connect (OSTI)

    Yang Jiaxiang; Lan Sheng; Xu Zuoming

    2008-05-05

    A virtual instrument technology is used to measure arc current, arc voltage, dynamic V-I characteristics, and nonlinear conductance for a cone-shaped water jet plasma arc under ac voltage. Experimental results show that ac arc discharge mainly happens in water vapor evaporated from water when heated. However, due to water's cooling effect and its conductance, arc conductance, reignition voltage, extinguish voltage, and current zero time are very different from those for ac arc discharge in gas work fluid. These can be valuable to further studies on mechanism and characteristics of plasma ac discharge in water, and even in gas work fluid.

  11. CREATING DYNAMIC EQUIVALENT PV CIRCUIT MODELS WITH IMPEDANCE SPECTROSCOPY FOR ARC FAULT MODELING

    E-Print Network [OSTI]

    CREATING DYNAMIC EQUIVALENT PV CIRCUIT MODELS WITH IMPEDANCE SPECTROSCOPY FOR ARC FAULT MODELING ® (NEC® ) requires new photovoltaic (PV) systems on or penetrating a building to include a listed arc of the arcing frequencies through PV components despite the potential for modules and other PV components

  12. Sensitivity analysis of a dynamic model for submerged arc silicon furnaces.

    E-Print Network [OSTI]

    Foss, Bjarne A.

    Sensitivity analysis of a dynamic model for submerged arc silicon furnaces. B. F. Lund1 , B. A for a dynamic model of submerged arc silicon furnaces. The model we study, called "Simod", was developed updating a nonlinear, dynamic model of a silicon furnace. We have identified a parameter set that has

  13. Dynamic Graphics in a GIS: A Link between ARC INFOTM and XGobi

    E-Print Network [OSTI]

    Symanzik, Jürgen

    Dynamic Graphics in a GIS: A Link between ARC INFOTM and XGobi Jurgen Symanzik1, James Majure2, Dianne Cook1, Noel Cressie1 1 Department of Statistics, Iowa State University, Ames, IA 50011, USA 2 GIS a link between a Geograph- ical Information System GIS, ARC INFOTM , and an in- teractive dynamic

  14. Atomic Scale Characterization of Compound Semiconductors Using Atom Probe Tomography

    SciTech Connect (OSTI)

    Gorman, B. P.; Norman, A. G.; Lawrence, D.; Prosa, T.; Guthrey, H.; Al-Jassim, M.

    2011-01-01

    Internal interfaces are critical in determining the performance of III-V multijunction solar cells. Studying these interfaces with atomic resolution using a combination of transmission electron microscopy (TEM), atom probe tomography (APT), and density functional calculations enables a more fundamental understanding of carrier dynamics in photovoltaic (PV) device structures. To achieve full atomic scale spatial and chemical resolution, data acquisition parameters in laser pulsed APT must be carefully studied to eliminate surface diffusion. Atom probe data with minimized group V ion clustering and expected stoichiometry can be achieved by adjusting laser pulse power, pulse repetition rate, and specimen preparation parameters such that heat flow away from the evaporating surface is maximized. Applying these improved analysis conditions to III-V based PV gives an atomic scale understanding of compositional and dopant profiles across interfaces and tunnel junctions and the initial stages of alloy clustering and dopant accumulation. Details on APT experimental methods and future in-situ instrumentation developments are illustrated.

  15. Dynamic Graphics in a GIS: A Link between ARC/INFO TM and XGobi

    E-Print Network [OSTI]

    Symanzik, Jürgen

    Dynamic Graphics in a GIS: A Link between ARC/INFO TM and XGobi J¨urgen Symanzik 1 , James Majure 2 GIS Support and Research Facility, Iowa State University symanzik@iastate.edu Abstract. This paper describes a link between a Geograph­ ical Information System (GIS), ARC/INFO TM , and an in­ teractive

  16. Dynamic Graphics in a GIS: A Bidirectional Link between ArcView 2.1TM and XGobi | An Update

    E-Print Network [OSTI]

    Symanzik, Jürgen

    Dynamic Graphics in a GIS: A Bidirectional Link between ArcView 2.1TM and XGobi | An Update J a Geographic Information System GIS, ArcView 2.1TM, and an interactive dynamic graphics program, XGobi. Arc to the integrationof a Geographic InformationSystem GIS,to be used for the display of spatial locations and concomitant

  17. Dynamic Graphics in a GIS: A Bidirectional Link between ArcView 2.1 TM and XGobi ---An Update

    E-Print Network [OSTI]

    Symanzik, Jürgen

    Dynamic Graphics in a GIS: A Bidirectional Link between ArcView 2.1 TM and XGobi --- An Update J a Geographic Information System (GIS), ArcView 2.1 TM , and an interactive dynamic graphics program, XGobi. Arc (GIS), to be used for the display of spatial locations and concomitant geographic variables

  18. Computational study of flow dynamics from a dc arc plasma jet

    E-Print Network [OSTI]

    Trelles, Juan Pablo

    2013-01-01

    Plasma jets produced by direct-current (DC) non-transferred arc plasma torches, at the core of technologies ranging from spray coating to pyrolysis, present intricate dynamics due to the coupled interaction of fluid flow, thermal, and electromagnetic phenomena. The flow dynamics from an arc discharge plasma jet are investigated using time-dependent three-dimensional simulations encompassing the dynamics of the arc inside the torch, the evolution of the jet through the discharge environment, and the subsequent impingement of the jet over a flat substrate. The plasma is described by a chemical equilibrium and thermodynamic nonequilibrium (two-temperature) model. The numerical formulation of the physical model is based on a monolithic and fully-coupled treatment of the fluid and electromagnetic equations using a Variational Multiscale Finite Element Method. Simulation results uncover distinct aspects of the flow dynamics, including the jet forcing due to the movement of the electric arc, the prevalence of deviat...

  19. The Linked ArcView 2.1TM and XGobi Environment --GIS, Dynamic Statistical Graphics, and Spatial Data

    E-Print Network [OSTI]

    Symanzik, Jürgen

    and geographic information systems. maintained within a geo- graphic information system (GIS). We developed a bidirectional link between Arc information system (GIS), ArcView 2.1TM, and an interactive dynamic graphics program in the X Window System

  20. Dynamic and spectroscopic characteristics of atmospheric gliding arc in gas-liquid two-phase flow

    SciTech Connect (OSTI)

    Tu, X.; Yu, L.; Yan, J. H.; Cen, K. F.; Cheron, B. G.

    2009-11-15

    In this study, an atmospheric alternating-current gliding arc device in gas-liquid two-phase flow has been developed for the purpose of waste water degradation. The dynamic behavior of the gas-liquid gliding arc is investigated through the oscillations of electrical signals, while the spatial evolution of the arc column is analyzed by high speed photography. Different arc breakdown regimes are reported, and the restrike mode is identified as the typical fluctuation characteristic of the hybrid gliding arc in air-water mixture. Optical emission spectroscopy is employed to investigate the active species generated in the gas-liquid plasma. The axial evolution of the OH (309 nm) intensity is determined, while the rotational and vibrational temperatures of the OH are obtained by a comparison between the experimental and simulated spectra. The significant discrepancy between the rotational and translational temperatures has also been discussed.

  1. Creating dynamic equivalent PV circuit models with impedance spectroscopy for arc-fault modeling.

    SciTech Connect (OSTI)

    Johnson, Jay Dean; Kuszmaul, Scott S.; Strauch, Jason E.; Schoenwald, David Alan

    2011-06-01

    Article 690.11 in the 2011 National Electrical Code{reg_sign} (NEC{reg_sign}) requires new photovoltaic (PV) systems on or penetrating a building to include a listed arc fault protection device. Currently there is little experimental or empirical research into the behavior of the arcing frequencies through PV components despite the potential for modules and other PV components to filter or attenuate arcing signatures that could render the arc detector ineffective. To model AC arcing signal propagation along PV strings, the well-studied DC diode models were found to inadequately capture the behavior of high frequency arcing signals. Instead dynamic equivalent circuit models of PV modules were required to describe the impedance for alternating currents in modules. The nonlinearities present in PV cells resulting from irradiance, temperature, frequency, and bias voltage variations make modeling these systems challenging. Linearized dynamic equivalent circuits were created for multiple PV module manufacturers and module technologies. The equivalent resistances and capacitances for the modules were determined using impedance spectroscopy with no bias voltage and no irradiance. The equivalent circuit model was employed to evaluate modules having irradiance conditions that could not be measured directly with the instrumentation. Although there was a wide range of circuit component values, the complex impedance model does not predict filtering of arc fault frequencies in PV strings for any irradiance level. Experimental results with no irradiance agree with the model and show nearly no attenuation for 1 Hz to 100 kHz input frequencies.

  2. Computational study of flow dynamics from a dc arc plasma jet

    E-Print Network [OSTI]

    Juan Pablo Trelles

    2013-03-15

    Plasma jets produced by direct-current (DC) non-transferred arc plasma torches, at the core of technologies ranging from spray coating to pyrolysis, present intricate dynamics due to the coupled interaction of fluid flow, thermal, and electromagnetic phenomena. The flow dynamics from an arc discharge plasma jet are investigated using time-dependent three-dimensional simulations encompassing the dynamics of the arc inside the torch, the evolution of the jet through the discharge environment, and the subsequent impingement of the jet over a flat substrate. The plasma is described by a chemical equilibrium and thermodynamic nonequilibrium (two-temperature) model. The numerical formulation of the physical model is based on a monolithic and fully-coupled treatment of the fluid and electromagnetic equations using a Variational Multiscale Finite Element Method. Simulation results uncover distinct aspects of the flow dynamics, including the jet forcing due to the movement of the electric arc, the prevalence of deviations between heavy-species and electron temperatures in the plasma fringes, the development of shear flow instabilities around the jet, the occurrence of localized regions with high electric fields far from the arc, and the formation and evolution of coherent flow structures.

  3. Modelling on dynamics properties of a stationary argon cascaded arc plasma flows

    SciTech Connect (OSTI)

    Wei, G. D.; Qi, X.; Yang, L.

    2014-03-15

    The gas dynamics properties of a stationary arc plasma flows are studied through the numerical simulations. A two dimensional axis-symmetric turbulent magneto-hydrodynamic plasma model is developed with the commercial code ANSYS FLUENT. The reliable ?-? model is used to account for turbulence. In this paper, the plasma is assumed to be a fluid following Navier–Stokes equations, respecting local thermodynamic equilibrium, and described by only one temperature. Distributions of the pressure, velocity, temperature, density, and electric potential inside of thus cascaded arc are obtained for an arc current density of 10{sup 6}?A/m{sup 2}. The pressure inside the arc varies from 10{sup 5}?Pa to 100?Pa. The temperature at the arc axis can reach as high as 13?600?K. The electric potential drops uniformly along the axis with a magnitude of 160?V. In addition, distributions of the sonic velocity and Mach number are shown to describe supersonic behavior of thus cascaded arc, which have a good agreement with the analytical formula.

  4. Discovery of novel hydrogen storage materials: an atomic scale...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Discovery of novel hydrogen storage materials: an atomic scale computational approach Home Author: C. Wolverton, D. J. Siegel, A. R. Akbarzadeh, V. Ozolins Year: 2008 Abstract:...

  5. In situ atomic-scale imaging of electrochemical lithiation in silicon

    E-Print Network [OSTI]

    Zhu, Ting

    -dependent mobility of the interfaces. L ithium-ion batteries are increasingly being used as energy storage devicesIn situ atomic-scale imaging of electrochemical lithiation in silicon Xiao Hua Liu1 *, Jiang Wei the dynamic lithiation process of single-crystal silicon with atomic resolution. We observe a sharp interface

  6. Dynamic Graphics in a GIS: A Bidirectional Link between ArcView 2.0TM and XGobi

    E-Print Network [OSTI]

    Symanzik, Jürgen

    Dynamic Graphics in a GIS: A Bidirectional Link between ArcView 2.0TM and XGobi Jurgen Symanzik1 GIS Support and Research Facility, Iowa State University symanzik@iastate.edu Abstract. In Symanzik et al. 1994 we have presented a link between a Geographic Information System GIS, ARC INFOTM

  7. Dynamic Graphics in a GIS: A Bidirectional Link between ArcView 2.0 TM and XGobi

    E-Print Network [OSTI]

    Symanzik, Jürgen

    Dynamic Graphics in a GIS: A Bidirectional Link between ArcView 2.0 TM and XGobi J¨urgen Symanzik 1 2 GIS Support and Research Facility, Iowa State University symanzik@iastate.edu Abstract. In Symanzik et al. (1994) we have presented a link between a Geographic Information System (GIS), ARC/INFO TM

  8. Atomic-Scale Observations Aid Mesoscale Catalyst Design | ornl...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Materials Characterization Atomic-Scale Observations Aid Mesoscale Catalyst Design April 08, 2015 Fig.1. Z-contrast STEM image shows the Mo-V-Te-Ta oxide catalyst. (a) "M1-like"...

  9. Tomographic study of atomic-scale redistribution of platinum...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Tomographic study of atomic-scale redistribution of platinum during the silicidation of Ni0.95Pt0.05Si(100) thin films Home Author: P. Adusumilli, L. J. Lauhon, D. N. Seidman, C....

  10. Atomic-scale electrochemistry on the surface of a manganite

    SciTech Connect (OSTI)

    Vasudevan, Rama K; Tselev, Alexander; Baddorf, Arthur P; Kalinin, Sergei V

    2015-01-01

    The doped manganese oxides (manganites) have been widely studied for their colossal magnetoresistive effects, for potential applications in oxide spintronics, electroforming in resistive switching devices, and are materials of choice as cathodes in modern solid oxide fuel cells. However, little experimental knowledge of the dynamics of the surfaces of perovskite manganites at the atomic scale exists. Here, through in-situ scanning tunnelling microscopy (STM), we demonstrate atomic resolution on samples of La0.625Ca0.375MnO3 grown on (001) SrTiO3 by pulsed laser deposition (PLD). Furthermore, by applying triangular DC waveforms of increasing amplitude to the STM tip, and measuring the tunnelling current, we demonstrate the ability to both perform and monitor surface electrochemical processes at the atomic level, including, for the first time in a manganite, formation of single and multiple oxygen vacancies, disruption of the overlying manganite layers, and removal and deposition of individual atomic units or clusters. Our work paves the way for better understanding of surface oxygen reactions in these systems.

  11. Atomic Scale Characterization of Compound Semiconductors using Atom Probe Tomography: Preprint

    SciTech Connect (OSTI)

    Gorman, B. P.; Guthrey, H.; Norman, A. G.; Al-Jassim, M.; Lawrence, D.; Prosa, T.

    2011-07-01

    Internal interfaces are critical in determining the performance of III-V multijunction solar cells. Studying these interfaces with atomic resolution using a combination of transmission electron microscopy (TEM), atom probe tomography (APT), and density functional calculations enables a more fundamental understanding of carrier dynamics in photovoltaic (PV) device structures. To achieve full atomic scale spatial and chemical resolution, data acquisition parameters in laser pulsed APT must be carefully studied to eliminate surface diffusion. Atom probe data with minimized group V ion clustering and expected stoichiometry can be achieved by adjusting laser pulse power, pulse repetition rate, and specimen preparation parameters such that heat flow away from the evaporating surface is maximized. Applying these improved analysis conditions to III-V based PV gives an atomic scale understanding of compositional and dopant profiles across interfaces and tunnel junctions and the initial stages of alloy clustering and dopant accumulation. Details on APT experimental methods and future in-situ instrumentation developments are illustrated.

  12. Atomic Scale Mechanism of Plutonium Corrosion Steven D. Conradson,1

    E-Print Network [OSTI]

    Atomic Scale Mechanism of Plutonium Corrosion Steven D. Conradson,1 Alison L. Costello,1 Francisco Estudios Superiores, Merida, Yucatan, Mexico conradson@lanl.gov INTRODUCTION The reaction of plutonium (Pu chemistry, nuclear forensics, and other areas of plutonium science and technology. The current model

  13. Atomic scale mixing for inertial confinement fusion associated hydro instabilities

    E-Print Network [OSTI]

    New York at Stoney Brook, State University of

    Atomic scale mixing for inertial confinement fusion associated hydro instabilities J. Melvina, , P Alamos, NM 87545, USA Abstract Hydro instabilities have been identified as a potential cause- able. We find numerical convergence for this important quantity, in a purely hydro study, with only

  14. High voltage dc--dc converter with dynamic voltage regulation and decoupling during load-generated arcs

    DOE Patents [OSTI]

    Shimer, D.W.; Lange, A.C.

    1995-05-23

    A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules. 5 Figs.

  15. High voltage dc-dc converter with dynamic voltage regulation and decoupling during load-generated arcs

    DOE Patents [OSTI]

    Shimer, Daniel W. (Danville, CA); Lange, Arnold C. (Livermore, CA)

    1995-01-01

    A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.

  16. Conduction in alumina with atomic scale copper filaments

    SciTech Connect (OSTI)

    Xu, Xu; Liu, Jie; Anantram, M. P.

    2014-10-28

    The conductance of atomic scale filaments with three and seven Cu atoms in ?-alumina are calculated using ab initio density functional theory. We find that the filament with 3 Cu atoms is sufficient to increase the conductance of 1.3?nm thick alumina film by more than 10{sup 3} times in linear response. As the applied voltage increases, the current quickly saturates and differential resistance becomes negative. Compared to the filament with three Cu atoms, while the conductance of the filament with seven Cu atoms is comparable in linear response, they carry as much as twenty times larger current at large biases. The electron transport is analyzed based on local density of states, and the negative differential resistance in the seven Cu filaments occurs due to their narrow bandwidth.

  17. Cathodic arcs

    E-Print Network [OSTI]

    Anders, Andre

    2003-01-01

    Rectangular vacuum-arc plasma source, Jan. 2, 1996. [40] A.A. Anders, Cathodic Arc Plasma Deposition (in preparation) (from the cathodic arc plasma. In most cases, a magnetic

  18. Effects of Stone-Wales and vacancy defects in atomic-scale friction on defective graphite

    SciTech Connect (OSTI)

    Sun, Xiao-Yu; Wu, RunNi; Xia, Re; Chu, Xi-Hua; Xu, Yuan-Jie

    2014-05-05

    Graphite is an excellent solid lubricant for surface coating, but its performance is significantly weakened by the vacancy or Stone-Wales (SW) defect. This study uses molecular dynamics simulations to explore the frictional behavior of a diamond tip sliding over a graphite which contains a single defect or stacked defects. Our results suggest that the friction on defective graphite shows a strong dependence on defect location and type. The 5-7-7-5 structure of SW defect results in an effectively negative slope of friction. For defective graphite containing a defect in the surface, adding a single vacancy in the interior layer will decrease the friction coefficients, while setting a SW defect in the interior layer may increase the friction coefficients. Our obtained results may provide useful information for understanding the atomic-scale friction properties of defective graphite.

  19. Atomic-scale Mechanisms of Helium Bubble hardening in Iron

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Osetskiy, Yury N.; Stoller, Roger E.

    2015-06-03

    Generation of helium due to (n, ) transmutation reactions changes the response of structural materials to neutron irradiation. The whole process of radiation damage evolution is affected by He accumulation and leads to significant changes in the material s properties. A population of nanometric He-filled bubbles affects mechanical properties and the impact can be quite significant because of their high density. Understanding how these basic mechanisms affect mechanical properties is necessary for predicting radiation effects. In this paper we present an extensive study of the interactions between a moving edge dislocation and bubbles using atomic-scale modeling. We focus on themore »effect of He bubble size and He concentration inside bubbles. We found that ability of bubbles to act as an obstacle to dislocation motion is close to that of voids when the He-to-vacancy ratio is in the range from 0 to 1. A few simulations made at higher He contents demonstrated that the interaction mechanism is changed for over-pressurized bubbles and they become weaker obstacles. The results are discussed in light of post-irradiation materials testing.« less

  20. Atomic-scale studies on the growth of palladium and titanium on GaN(0001)

    E-Print Network [OSTI]

    Castell, Martin

    Atomic-scale studies on the growth of palladium and titanium on GaN(0001) C. No¨renberg a,b,*, M nitride; Palladium; Titanium; Alloys; Epitaxy; Metal­semiconductor interfaces; Nanostructures; Scanning;Here, we have focused on atomic-scale studies of the ini- tial growth stages of palladium and titanium

  1. Atomic-scale electron-beam sculpting of defect-free graphene nanostructures

    E-Print Network [OSTI]

    Dekker, Cees

    Atomic-scale electron-beam sculpting of defect-free graphene nanostructures Bo Song, Grégory F.w.zandbergen@tudelft.nl ABSTRACT. In order to harvest the many promising properties of graphene in (electronic) applications a temperature-dependent self-repair mechanism allowing damage-free atomic-scale sculpting of graphene using

  2. Atomic-scale electrochemistry on the surface of a manganite by scanning tunneling microscopy

    SciTech Connect (OSTI)

    Vasudevan, Rama K. Tselev, Alexander; Baddorf, Arthur P.; Gianfrancesco, Anthony G.

    2015-04-06

    The doped manganese oxides (manganites) have been widely studied for their colossal magnetoresistive effects, for potential applications in oxide spintronics, electroforming in resistive switching devices, and are materials of choice as cathodes in modern solid oxide fuel cells. However, little experimental knowledge of the dynamics of the surfaces of perovskite manganites at the atomic scale exists. Here, through in-situ scanning tunneling microscopy (STM), we demonstrate atomic resolution on samples of La{sub 0.625}Ca{sub 0.375}MnO{sub 3} grown on (001) SrTiO{sub 3} by pulsed laser deposition. Furthermore, by applying triangular DC waveforms of increasing amplitude to the STM tip, and measuring the tunneling current, we demonstrate the ability to both perform and monitor surface electrochemical processes at the atomic level, including formation of oxygen vacancies and removal and deposition of individual atomic units or clusters. Our work paves the way for better understanding of surface oxygen reactions in these systems.

  3. Architecture of the Object Oriented ARC framework

    E-Print Network [OSTI]

    Joshi, Rushikesh K.

    in the ARC logical ring ARC Sotware Components ARC Sotware Components ARC Sotware Components ARC Sotware Components ARC Sotware Components > > >

  4. The ArcSDE GIS Dynamic Population Model Tool for Savannah River Site Emergency Response

    SciTech Connect (OSTI)

    MCLANE, TRACY; JONES, DWIGHT

    2005-10-03

    The Savannah River Site (SRS) is a 310-square-mile Department of Energy site located near Aiken, South Carolina. With a workforce of over 10,000 employees and subcontractors, SRS emergency personnel must be able to respond to an emergency event in a timely and effective manner, in order to ensure the safety and security of the Site. Geographic Information Systems (GIS) provides the technology needed to give managers and emergency personnel the information they need to make quick and effective decisions. In the event of a site evacuation, knowing the number of on-site personnel to evacuate from a given area is an essential piece of information for emergency staff. SRS has developed a GIS Dynamic Population Model Tool to quickly communicate real-time information that summarizes employee populations by facility area and building and then generates dynamic maps that illustrate output statistics.

  5. A new Embedded Atom Method potential for atomic-scale modeling of metal-silicon systems

    E-Print Network [OSTI]

    Zhigilei, Leonid V.

    A new Embedded Atom Method potential for atomic-scale modeling of metal-silicon systems Avinash M efficient interatomic potentials for metal-silicon systems. For metals, the Embedded Atom Method (EAM) [1 for the description of interatomic interactions in metal-silicon systems. The potential is based on reformulation

  6. An atomic-scale analysis of catalytically-assisted chemical vapor deposition of carbon nanotubes

    E-Print Network [OSTI]

    Grujicic, Mica

    ) their unique structure makes them suitable for tailored nanometer- scale membranes and molecular sieves [5]; (dAn atomic-scale analysis of catalytically-assisted chemical vapor deposition of carbon nanotubes M Growth of carbon nanotubes during transition-metal particles catalytically-assisted thermal decomposition

  7. Atomic-Scale Mapping of Thermoelectric Power on Graphene: Role of Defects and Boundaries

    E-Print Network [OSTI]

    Feenstra, Randall

    1 Atomic-Scale Mapping of Thermoelectric Power on Graphene: Role of Defects and Boundaries Jewook University, Pittsburgh, PA 15213, USA Abstract The spatially resolved thermoelectric power is studied on epitaxial graphene on SiC with direct correspondence to graphene atomic structures by a scanning tunneling

  8. Arc Plasma Torch Modeling

    E-Print Network [OSTI]

    Trelles, J P; Vardelle, A; Heberlein, J V R

    2013-01-01

    Arc plasma torches are the primary components of various industrial thermal plasma processes involving plasma spraying, metal cutting and welding, thermal plasma CVD, metal melting and remelting, waste treatment and gas production. They are relatively simple devices whose operation implies intricate thermal, chemical, electrical, and fluid dynamics phenomena. Modeling may be used as a means to better understand the physical processes involved in their operation. This paper presents an overview of the main aspects involved in the modeling of DC arc plasma torches: the mathematical models including thermodynamic and chemical non-equilibrium models, turbulent and radiative transport, thermodynamic and transport property calculation, boundary conditions and arc reattachment models. It focuses on the conventional plasma torches used for plasma spraying that include a hot-cathode and a nozzle anode.

  9. 3-D Atomic-Scale Mapping of Manganese Dopants in Lead Sulfide Nanowires

    SciTech Connect (OSTI)

    Isheim, Dieter; Kaszpurenko, Jason; Yu, Dong; Mao, Zugang; Seidman, David N.; Arslan, Ilke

    2012-03-22

    Dopants in nanowires, whether intentional or unintentional, can ultimately control the material's properties and therefore need to be understood on the atomic scale. We study vapor-liquid-solid grown manganese-doped lead sulfide nanowires by atom-probe tomography for the first time for lead salt materials. The three-dimensional chemical concentration maps at the atomic scale demonstrate a radial distribution profile of Mn ions, with a concentration of only 0.18 at.% and 0.01 at.% for MnCl2 and Mn-acetate precursors, respectively. The ability to characterize these small concentrations of dopant atoms in Pb1-xMnxS nanowires (x = 0.0036 and 0.0002), important for spintronic and thermoelectric devices, sets a platform for similar analyses for all nanostructures. First-principles calculations confirm that Mn atoms substitute for Pb in the PbS structure.

  10. Three-dimensional modeling of the plasma arc in arc welding

    SciTech Connect (OSTI)

    Xu, G.; Tsai, H. L.; Hu, J.

    2008-11-15

    Most previous three-dimensional modeling on gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) focuses on the weld pool dynamics and assumes the two-dimensional axisymmetric Gaussian distributions for plasma arc pressure and heat flux. In this article, a three-dimensional plasma arc model is developed, and the distributions of velocity, pressure, temperature, current density, and magnetic field of the plasma arc are calculated by solving the conservation equations of mass, momentum, and energy, as well as part of the Maxwell's equations. This three-dimensional model can be used to study the nonaxisymmetric plasma arc caused by external perturbations such as an external magnetic field. It also provides more accurate boundary conditions when modeling the weld pool dynamics. The present work lays a foundation for true three-dimensional comprehensive modeling of GTAW and GMAW including the plasma arc, weld pool, and/or electrode.

  11. Arc Position Sensing

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    device. Basically, an ECL can determine positions of arcs within an electric arc furnace in real time. No other measurement technique can give this kind of information....

  12. Method for large-scale fabrication of atomic-scale structures on material surfaces using surface vacancies

    DOE Patents [OSTI]

    Lim, Chong Wee (Urbana, IL); Ohmori, Kenji (Urbana, IL); Petrov, Ivan Georgiev (Champaign, IL); Greene, Joseph E. (Champaign, IL)

    2004-07-13

    A method for forming atomic-scale structures on a surface of a substrate on a large-scale includes creating a predetermined amount of surface vacancies on the surface of the substrate by removing an amount of atoms on the surface of the material corresponding to the predetermined amount of the surface vacancies. Once the surface vacancies have been created, atoms of a desired structure material are deposited on the surface of the substrate to enable the surface vacancies and the atoms of the structure material to interact. The interaction causes the atoms of the structure material to form the atomic-scale structures.

  13. Atomic Scale Imaging of the Electronic Structure and Chemistry of Graphene and Its Precursors on Metal Surfaces

    SciTech Connect (OSTI)

    Flynn, George W

    2015-02-16

    Executive Summary of Final Report for Award DE-FG02-88ER13937 Project Title: Atomic Scale Imaging of the Electronic Structure and Chemistry of Graphene and its Precursors on Metal Surfaces Applicant/Institution: Columbia University Principal Investigator: George W. Flynn Objectives: The objectives of this project were to reveal the mechanisms and reaction processes that solid carbon materials undergo when combining with gases such as oxygen, water vapor and hydrocarbons. This research was focused on fundamental chemical events taking place on single carbon sheets of graphene, a two-dimensional, polycyclic carbon material that possesses remarkable chemical and electronic properties. Ultimately, this work is related to the role of these materials in mediating the formation of polycyclic aromatic hydrocarbons (PAH’s), their reactions at interfaces, and the growth of soot particles. Our intent has been to contribute to a fundamental understanding of carbon chemistry and the mechanisms that control the formation of PAH’s, which eventually lead to the growth of undesirable particulates. We expect increased understanding of these basic chemical mechanisms to spur development of techniques for more efficient combustion of fossil fuels and to lead to a concomitant reduction in the production of undesirable solid carbon material. Project Description: Our work treated specifically the surface chemistry aspects of carbon reactions by using proximal probe (atomic scale imaging) techniques to study model systems of graphene that have many features in common with soot forming reactions of importance in combustion flames. Scanning tunneling microscopy (STM) is the main probe technique that we used to study the interfacial structure and chemistry of graphene, mainly because of its ability to elucidate surface structure and dynamics with molecular or even atomic resolution. Scanning tunneling spectroscopy (STS), which measures the local density of quantum states over a single atom, provides information about the electronic structure of graphene and is particularly sensitive to the sign and magnitude of the charge transfer between graphene and any surface adsorbed species. Results: (A) Graphene on SiO2 In an effort designed to unravel aspects of the mechanisms for chemistry on graphene surfaces, STM and STS were employed to show that graphene on SiO2 is oxidized at lower temperatures than either graphite or multi-layer graphene. Two independent factors control this charge transfer: (1) the degree of graphene coupling to the substrate, and (2) exposure to oxygen and moisture. (B) Graphene on Copper In the case of graphene grown on copper surfaces, we found that the graphene grows primarily in registry with the underlying copper lattice for both Cu(111) and Cu(100). On Cu(111) the graphene has a hexagonal superstructure with a significant electronic component, whereas it has a linear superstructure on Cu(100). (C) Nitrogen Doped Graphene on Copper Using STM we have also studied the electronic structure and morphology of graphene films grown on a copper foil substrate in which N atoms substitute for carbon in the 2-D graphene lattice. The salient features of the results of this study were: (1) Nitrogen doped graphene on Cu foil exhibits a triangular structure with an “apparent” slight elevation of ~ 0.8 Å at N atom substitution sites; (2) Nitrogen doping results in ~0.4 electrons per N atom donated to the graphene lattice; (3) Typical N doping of graphene on Cu foil shows mostly single site Carbon atom displacement (~ 3N/1000C); (4) Some multi-site C atom displacement is observed (<10% of single site events). (D) Boron Doped Graphene on Copper We also used scanning tunneling microscopy and x-ray spectroscopy to characterize the atomic and electronic structure of boron-doped graphene created by chemical vapor deposition on copper substrates. Microscopic measurements show that boron, like nitrogen, incorporates into the carbon lattice primarily in the graphitic form and contributes ~0.5 free carriers into the graphene sheet per dopa

  14. 14 IEEE ELECTRON DEVICE LETTERS, VOL. 22, NO. 1, JANUARY 2001 Atomic Scale Effects of Zirconium and Hafnium

    E-Print Network [OSTI]

    Dutton, Robert W.

    14 IEEE ELECTRON DEVICE LETTERS, VOL. 22, NO. 1, JANUARY 2001 Atomic Scale Effects of Zirconium Abstract--First principles calculations aimed at quantifying the effects of zirconium and hafnium]. For any proposed material, achieving a high quality interface with silicon (Si) is essential. Zirconium

  15. Atomic-scale imaging and the effect of yttrium on the fracture toughness of silicon carbide ceramics

    E-Print Network [OSTI]

    Ritchie, Robert

    Atomic-scale imaging and the effect of yttrium on the fracture toughness of silicon carbide boundary pro- motes transgranular fracture by raising the modulus of the nanoscale intergranular grain; Silicon carbide; Yttrium dopants; Fracture toughness 1. Introduction Rare-earth (RE) additives

  16. Rotating arc spark plug

    DOE Patents [OSTI]

    Whealton, John H.; Tsai, Chin-Chi

    2003-05-27

    A spark plug device includes a structure for modification of an arc, the modification including arc rotation. The spark plug can be used in a combustion engine to reduce emissions and/or improve fuel economy. A method for operating a spark plug and a combustion engine having the spark plug device includes the step of modifying an arc, the modifying including rotating the arc.

  17. Observation of atomic scale compositional and displacive modulations in incommensurate melilite electrolytes

    SciTech Connect (OSTI)

    Wei, Fengxia [Division of Materials Science and Engineering, Nanyang Technological University (Singapore); Williams, Tim [Monash Centre for Electron Microscopy, Monash University, Melbourne (Australia); An, Tao; Baikie, Tom; Kloc, Christian [Division of Materials Science and Engineering, Nanyang Technological University (Singapore); Wei, Jun [Singapore Institute of Manufacturing Technology, Agency for Science Technology and Research (Singapore); White, Tim, E-mail: tjwhite@ntu.edu.sg [Division of Materials Science and Engineering, Nanyang Technological University (Singapore)

    2013-07-15

    The paradigm that functional materials are adequately described as three-dimensional crystal structures is not universally tenable. Gallate melilites are efficient oxide ion conductors at intermediate temperatures (?750 °C) with non-rational crystallographic modulations presumed to play a key role in significantly enhancing oxygen mobility. Lattice distortions associated with incommensuration are usually extrapolated from diffraction analysis of volumes greatly exceeding the scale of modulation. Therefore, opportunities for making direct nanometric measurements are exceptionally valuable for correlating structure with function. In [CaLn]{sub 2}[Ga]{sub 2}[Ga{sub 2}O{sub 7}]{sub 2} (Ln=Nd, La) melilites, atomic displacive and compositional modulation waves can be imaged by high angle annular dark field and bright field scanning transmission electron microscopy with contrast quantified through electron scattering simulation. Here, we present atomic scale observations of (3+2)-dimensional modulations in gallate melilites which expands our understanding of the ion conduction mechanism and provides guidance for enhancing the performance of solid oxide fuel cells through crystal chemical tailoring. - Highlights: • Characterise the (3+2)-dimensional melilite electrolytes using STEM technique. • Direct observation on displacive and compositional modulation in melilites. • Structural flexibility reduces when increasing interstitial oxygen. • Domain-like incommensurate modulation model is proposed.

  18. DC arc weld starter

    DOE Patents [OSTI]

    Campiotti, Richard H. (Tracy, CA); Hopwood, James E. (Oakley, CA)

    1990-01-01

    A system for starting an arc for welding uses three DC power supplies, a high voltage supply for initiating the arc, an intermediate voltage supply for sustaining the arc, and a low voltage welding supply directly connected across the gap after the high voltage supply is disconnected.

  19. Formation of ion irradiation-induced atomic-scale defects on walls of carbon nanotubes A. V. Krasheninnikova b, K. Nordlundb, M. Sirviob, E. Salonenb and J. Keinonenb

    E-Print Network [OSTI]

    Nordlund, Kai

    Formation of ion irradiation-induced atomic-scale defects on walls of carbon nanotubes A. V.O. Box 43, FIN-00014 University of Helsinki, Finland (March 20, 2001) Recent experiments on irradiated structure and formation probabilities of atomic-scale defects produced by low-dose irradi- ation

  20. Atomic-scale evolution of modulated phases at the ferroelectric-antiferroelectric morphotropic phase boundary controlled by flexoelectric interaction

    SciTech Connect (OSTI)

    Borisevich, Albina Y; Eliseev, Eugene; Morozovska, A. N.; Cheng, Ching-Jung; Lin, Jiunn-Yuan; Chu, Ying-Hao; Kan, Daisuke; Takeuchi, Ichiro; Valanoor, Nagarajan V; Kalinin, Sergei V

    2012-01-01

    Physical and structural origins of morphotropic phase boundaries (MPBs) in ferroics remain elusive despite decades of studies. The leading competing theories employ either low symmetry bridging phases or adaptive phases with nanoscale textures to describe different subsets of the macroscopic data, while the decisive atomic-scale information has so far been missing. We report direct atomically-resolved mapping of polarization and structure order parameter fields in Sm-doped BiFeO3 system and their evolution as the system approaches MPB. We further show that both the experimental phase diagram and the phase evolution observed by STEM can be explained by taking into account flexoelectric interaction, which renders the effective domain wall energy negative, thus stabilizing modulated phases in the vicinity of the MPB. Our study highlights the importance of local order parameter mapping at the atomic scale and establishes a hitherto unobserved physical origin of spatially modulated phases existing in the vicinity of the MPB.

  1. Arc initiation in cathodic arc plasma sources

    DOE Patents [OSTI]

    Anders, Andre (Albany, CA)

    2002-01-01

    A "triggerless" arc initiation method and apparatus is based on simply switching the arc supply voltage to the electrodes (anode and cathode). Neither a mechanical trigger electrode nor a high voltage flashover from a trigger electrode is required. A conducting path between the anode and cathode is provided, which allows a hot spot to form at a location where the path connects to the cathode. While the conductive path is eroded by the cathode spot action, plasma deposition ensures the ongoing repair of the conducting path. Arc initiation is achieved by simply applying the relatively low voltage of the arc power supply, e.g. 500 V-1 kV, with the insulator between the anode and cathode coated with a conducting layer and the current at the layer-cathode interface concentrated at one or a few contact points. The local power density at these contact points is sufficient for plasma production and thus arc initiation. A conductive surface layer, such as graphite or the material being deposited, is formed on the surface of the insulator which separates the cathode from the anode. The mechanism of plasma production (and arc initiation) is based on explosive destruction of the layer-cathode interface caused by joule heating. The current flow between the thin insulator coating and cathode occurs at only a few contact points so the current density is high.

  2. Energy-loss- and thickness-dependent contrast in atomic-scale electron energy-loss spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tan, Haiyan [Universit_e de Toulouse, Toulouse, France (Europe); National Institute of Standards Technology, Gaithersburg, MD (United States); Xin, Huolin L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zhu, Ye [Monash Univ., Melbourne, VIC (Australia); Dwyer, Christian [Peter Grunberg Institute, Julich, Germany (Europe)

    2014-12-01

    Atomic-scale elemental maps of materials acquired by core-loss inelastic electron scattering often exhibit an undesirable sensitivity to the unavoidable elastic scattering, making the maps counter-intuitive to interpret. Here, we present a systematic study that scrutinizes the energy-loss and sample-thickness dependence of atomic-scale elemental maps acquired using 100 keV incident electrons in a scanning transmission electron microscope. For single-crystal silicon, the balance between elastic and inelastic scattering means that maps generated from the near-threshold Si-L signal (energy loss of 99 eV) show no discernible contrast for a thickness of 0.5? (? is the electron mean-free path, here approximately 110 nm). At greater thicknesses we observe a counter-intuitive “negative” contrast. Only at much higher energy losses is an intuitive “positive” contrast gradually restored. Our quantitative analysis shows that the energy-loss at which a positive contrast is restored depends linearly on the sample thickness. This behavior is in very good agreement with our double-channeling inelastic scattering calculations. We test a recently-proposed experimental method to correct the core-loss inelastic scattering and restore an intuitive “positive” chemical contrast. The method is demonstrated to be reliable over a large range of energy losses and sample thicknesses. The corrected contrast for near-threshold maps is demonstrated to be (desirably) inversely proportional to sample thickness. Implications for the interpretation of atomic-scale elemental maps are discussed.

  3. Atomic-Scale Chemical Imaging and Quantification of Metallic Alloy Structures by Energy-Dispersive X-Ray Spectroscopy

    SciTech Connect (OSTI)

    Lu, Ping [Sandia National Laboratories; Zhou, Lin [Ames Laboratory; Kramer, Matthew J. [Ames Laboratory; Smith, David J. [Arizona State University

    2014-02-04

    Determination of atomic-scale crystal structure for nanostructured intermetallic alloys, such as magnetic alloys containing Al, Ni, Co (alnico) and Fe, is crucial for understanding physical properties such as magnetism, but technically challenging due to the small interatomic distances and the similar atomic numbers. By applying energy-dispersive X-ray spectroscopy (EDS) mapping to the study of two intermetallic phases of an alnico alloy resulting from spinodal decomposition, we have determined atomic-scale chemical composition at individual lattice sites for the two phases: one is the B2 phase with Fe0.76Co0.24 -Fe0.40Co0.60 ordering and the other is the L21 phase with Ni0.48Co0.52 at A-sites, Al at B?-sites and Fe0.20Ti0.80 at B??-sites, respectively. The technique developed through this study represents a powerful real-space approach to investigate structure chemically at the atomic scale for a wide range of materials systems.

  4. Effects of shielding gas compositions on arc plasma and metal transfer in gas metal arc welding

    SciTech Connect (OSTI)

    Rao, Z. H.; Liao, S. M.; Tsai, H. L.

    2010-02-15

    This article presents the effects of shielding gas compositions on the transient transport phenomena, including the distributions of temperature, flow velocity, current density, and electromagnetic force in the arc and the metal, and arc pressure in gas metal arc welding of mild steel at a constant current input. The shielding gas considered includes pure argon, 75% Ar, 50% Ar, and 25% Ar with the balance of helium. It is found that the shielding gas composition has significant influences on the arc characteristics; droplet formation, detachment, transfer, and impingement onto the workpiece; and weld pool dynamics and weld bead profile. As helium increases in the shielding gas, the droplet size increases but the droplet detachment frequency decreases. For helium-rich gases, the current converges at the workpiece with a 'ring' shape which produces non-Gaussian-like distributions of arc pressure and temperature along the workpiece surface. Detailed explanations to the physics of the very complex but interesting transport phenomena are given.

  5. Rates of tectonic and magmatic processes in the North Cascades continental magmatic arc

    E-Print Network [OSTI]

    Matzel, Jennifer E. Piontek, 1973-

    2004-01-01

    Continental magmatic arcs are among the most dynamic. geologic systems, and documentation of the magmatic, thermal, and tectonic evolution of arcs is essential for understanding the processes of magma generation, ascent ...

  6. SU P ER C O N D U C T O R S Imaging atomic-scale effects of high-energy ion

    E-Print Network [OSTI]

    Davis, James C.

    annihilated within the former and suppressed by the latter. Simultaneous atomically resolved images for suchmaterials engineering requires specific atomic-scale knowledge, in- cluding the structure of ion achieved by scanning tunneling microscopy (STM). However, to our knowledge, simultaneous atomic

  7. Plasticity of metallic nanostructures : molecular dynamics simulations 

    E-Print Network [OSTI]

    Healy, Con

    2014-11-27

    During high speed cutting processes, metals are subject to high strains and strain rates. The dynamic nature of the deformation during high speed cutting makes it difficult to detect atomic scale deformation mechanisms ...

  8. Energy-loss- and thickness-dependent contrast in atomic-scale electron energy-loss spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tan, Haiyan; Zhu, Ye; Dwyer, Christian; Xin, Huolin L.

    2014-12-31

    Atomic-scale elemental maps of materials acquired by core-loss inelastic electron scattering often exhibit an undesirable sensitivity to the unavoidable elastic scattering, making the maps counter-intuitive to interpret. Here, we present a systematic study that scrutinizes the energy-loss and sample-thickness dependence of atomic-scale elemental maps acquired using 100 keV incident electrons in a scanning transmission electron microscope. For single-crystal silicon, the balance between elastic and inelastic scattering means that maps generated from the near-threshold Si-L signal (energy loss of 99 eV) show no discernible contrast for a thickness of 0.5? (? is the electron mean-free path, here approximately 110 nm). Atmore »greater thicknesses we observe a counter-intuitive “negative” contrast. Only at much higher energy losses is an intuitive “positive” contrast gradually restored. Our quantitative analysis shows that the energy-loss at which a positive contrast is restored depends linearly on the sample thickness. This behavior is in very good agreement with our double-channeling inelastic scattering calculations. We test a recently-proposed experimental method to correct the core-loss inelastic scattering and restore an intuitive “positive” chemical contrast. The method is demonstrated to be reliable over a large range of energy losses and sample thicknesses. The corrected contrast for near-threshold maps is demonstrated to be (desirably) inversely proportional to sample thickness. As a result, implications for the interpretation of atomic-scale elemental maps are discussed.« less

  9. Energy-loss- and thickness-dependent contrast in atomic-scale electron energy-loss spectroscopy

    SciTech Connect (OSTI)

    Tan, Haiyan; Zhu, Ye; Dwyer, Christian; Xin, Huolin L.

    2014-12-31

    Atomic-scale elemental maps of materials acquired by core-loss inelastic electron scattering often exhibit an undesirable sensitivity to the unavoidable elastic scattering, making the maps counter-intuitive to interpret. Here, we present a systematic study that scrutinizes the energy-loss and sample-thickness dependence of atomic-scale elemental maps acquired using 100 keV incident electrons in a scanning transmission electron microscope. For single-crystal silicon, the balance between elastic and inelastic scattering means that maps generated from the near-threshold Si-L signal (energy loss of 99 eV) show no discernible contrast for a thickness of 0.5? (? is the electron mean-free path, here approximately 110 nm). At greater thicknesses we observe a counter-intuitive “negative” contrast. Only at much higher energy losses is an intuitive “positive” contrast gradually restored. Our quantitative analysis shows that the energy-loss at which a positive contrast is restored depends linearly on the sample thickness. This behavior is in very good agreement with our double-channeling inelastic scattering calculations. We test a recently-proposed experimental method to correct the core-loss inelastic scattering and restore an intuitive “positive” chemical contrast. The method is demonstrated to be reliable over a large range of energy losses and sample thicknesses. The corrected contrast for near-threshold maps is demonstrated to be (desirably) inversely proportional to sample thickness. As a result, implications for the interpretation of atomic-scale elemental maps are discussed.

  10. Welding arc initiator

    DOE Patents [OSTI]

    Correy, T.B.

    1989-05-09

    An improved inert gas shielded tungsten arc welder is disclosed of the type wherein a tungsten electrode is shielded within a flowing inert gas, and, an arc, following ignition, burns between the energized tungsten electrode and a workpiece. The improvement comprises in combination with the tungsten electrode, a starting laser focused upon the tungsten electrode which to ignite the electrode heats a spot on the energized electrode sufficient for formation of a thermionic arc. Interference problems associated with high frequency starters are thus overcome. 3 figs.

  11. Electric arc saw apparatus

    DOE Patents [OSTI]

    Deichelbohrer, Paul R [Richland, WA

    1986-01-01

    A portable, hand held electric arc saw has a small frame for supporting an electrically conducting rotary blade which serves as an electrode for generating an electric arc to erode a workpiece. Electric current is supplied to the blade by biased brushes and a slip ring which are mounted in the frame. A pair of freely movable endless belts in the form of crawler treads stretched between two pulleys are used to facilitate movement of the electric arc saw. The pulleys are formed of dielectric material to electrically insulate the crawler treads from the frame.

  12. Numerical investigation of the double-arcing phenomenon in a cutting arc torch

    SciTech Connect (OSTI)

    Mancinelli, B. R.; Minotti, F. O.; Kelly, H.; Prevosto, L.

    2014-07-14

    A numerical investigation of the double-arcing phenomenon in a cutting arc torch is reported. The dynamics of the double-arcing were simulated by using a two-dimensional model of the gas breakdown development in the space-charge layer contiguous to the nozzle of a cutting arc torch operated with oxygen. The kinetic scheme includes ionization of heavy particles by electron impact, electron attachment, electron detachment, electron–ion recombination, and ion–ion recombination. Complementary measurements during double-arcing phenomena were also conducted. A marked rise of the nozzle voltage was found. The numerical results showed that the dynamics of a cathode spot at the exit of the nozzle inner surface play a key role in the raising of the nozzle voltage, which in turn allows more electrons to return to the wall at the nozzle inlet. The return flow of electrons thus closes the current loop of the double-arcing. The increase in the (floating) nozzle voltage is due to the fact that the increased electron emission at the spot is mainly compensated by the displacement current (the ions do not play a relevant role due to its low-mobility) until that the stationary state is achieved and the electron return flow fully-compensates the electron emission at the spot. A fairly good agreement was found between the model and the experiment for a spot emission current growth rate of the order of 7?×?10{sup 4}?A/s.

  13. Filtered cathodic arc source

    DOE Patents [OSTI]

    Falabella, S.; Sanders, D.M.

    1994-01-18

    A continuous, cathodic arc ion source coupled to a macro-particle filter capable of separation or elimination of macro-particles from the ion flux produced by cathodic arc discharge is described. The ion source employs an axial magnetic field on a cathode (target) having tapered sides to confine the arc, thereby providing high target material utilization. A bent magnetic field is used to guide the metal ions from the target to the part to be coated. The macro-particle filter consists of two straight solenoids, end to end, but placed at 45[degree] to one another, which prevents line-of-sight from the arc spot on the target to the parts to be coated, yet provides a path for ions and electrons to flow, and includes a series of baffles for trapping the macro-particles. 3 figures.

  14. Electric arc saw apparatus

    DOE Patents [OSTI]

    Deichelbohrer, P.R.

    1983-08-08

    A portable, hand-held electric arc saw apparatus comprising a small frame for supporting an electrically conducting rotary blade which serves as an electrode for generating an electric arc between the blade and a workpiece of opposite polarity. Electrically conducting means are provided on said frame for transmitting current to said blade. A pair of freely movable endless belts in the form of crawler treads are employed to facilitate movement of the apparatus relative to the workpiece.

  15. Local structures of high-entropy alloys (HEAs) on atomic scales: An overview

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Diao, Haoyan; Santodonato, Louis J.; Tang, Zhi; Egami, Takeshi; Liaw, Peter K.

    2015-08-29

    The high-entropy alloys, containing several elements mixed in equimolar or near-equimolar ratios, have shown exceptional engineering properties. Local structures on the atomic level are essential to understand the mechanical behaviors and related mechanisms. This article covers the local structure and stress on the atomic level are reviewed by the pair-distribution function of neutron-diffraction data, ab-initio molecular dynamics simulations, and the atomic probe microscopy.

  16. Theory of Parabolic Arcs in Interstellar Scintillation Spectra

    E-Print Network [OSTI]

    James M. Cordes; Barney J. Rickett; Daniel R. Stinebring; William A. Coles

    2004-07-03

    Our theory relates the secondary spectrum, the 2D power spectrum of the radio dynamic spectrum, to the scattered pulsar image in a thin scattering screen geometry. Recently discovered parabolic arcs in secondary spectra are generic features for media that scatter radiation at angles much larger than the rms scattering angle. Each point in the secondary spectrum maps particular values of differential arrival-time delay and fringe rate (or differential Doppler frequency) between pairs of components in the scattered image. Arcs correspond to a parabolic relation between these quantities through their common dependence on the angle of arrival of scattered components. Arcs appear even without consideration of the dispersive nature of the plasma. Arcs are more prominent in media with negligible inner scale and with shallow wavenumber spectra, such as the Kolmogorov spectrum, and when the scattered image is elongated along the velocity direction. The arc phenomenon can be used, therefore, to constrain the inner scale and the anisotropy of scattering irregularities for directions to nearby pulsars. Arcs are truncated by finite source size and thus provide sub micro arc sec resolution for probing emission regions in pulsars and compact active galactic nuclei. Multiple arcs sometimes seen signify two or more discrete scattering screens along the propagation path, and small arclets oriented oppositely to the main arc persisting for long durations indicate the occurrence of long-term multiple images from the scattering screen.

  17. Ion charge state fluctuations in vacuum arcs

    E-Print Network [OSTI]

    Anders, Andre; Fukuda, Kentaro; Yushkov, Georgy Yu

    2004-01-01

    known that cathodic vacuum arc plasmas contain multiple ionfunctions [16]. The arc plasma is known to be “noisy,” thatcondensation of cathodic arc plasma. They are also used as

  18. Atomic Scale Modelling of the Primary Damage State of Irradiated UO{sub 2} Matrix

    SciTech Connect (OSTI)

    Van Brutzel, Laurent

    2008-07-01

    Large scale classical molecular dynamics simulations have been carried out to study the primary damage state due to a-decay self irradiation in UO{sub 2} matrix. Simulations of energetic displacement cascades up to the realistic energy of the recoil nucleus at 80 keV provide new informations on defect production, their spatial distribution and their clustering. The discrepancy with the classical linear theory NRT (Norton-Robinson-Torrens) law on the creation of the number of point defects is discussed. Study of cascade overlap sequence shows a saturation of the number of point defects created as the dose increases. Toward the end of the overlap sequence, large stable clusters of vacancies are observed. The values of athermal diffusion coefficients coming from the ballistic collisions and the additional point defects created during the cascades are estimated from these simulations to be, in all the cases, less than 10-26 m{sup 2}/s. Finally, the influence of a grain boundary of type Sigma 5 is analysed. It has been found that the energy of the cascades are dissipated along the interface and that most of the point defects are created at the grain boundary. (authors)

  19. Chopping effect observed at cathodic arc initiation

    E-Print Network [OSTI]

    Anders, Andre

    2000-01-01

    generation by vacuum arc plasma guns,” Rev. Sci. Instrum. ,probe L L SCR C C D I arc plasma source and filter cathode Rto IEEE Trans. Plasma Science Cathodic arcs or “vacuum” arcs

  20. Formation of ion-irradiation-induced atomic-scale defects on walls of carbon nanotubes A. V. Krasheninnikov,1,2

    E-Print Network [OSTI]

    Krasheninnikov, Arkady V.

    Formation of ion-irradiation-induced atomic-scale defects on walls of carbon nanotubes A. V Recent experiments on irradiated carbon nanotubes provide evidence that ion bombardment gives rise tunneling microscopy STM images of irradiated nanotubes. We demonstrate that irradiation-induced defects may

  1. Atomic-scale identification of Pd leaching in nanoparticle catalyzed C–C coupling: Effects of particle surface disorder

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Briggs, Beverly D.; Bedford, Nicholas M.; Seifert, Soenke; Koerner, Hilmar; Ramezani-Dakhel, Hadi; Heinz, Hendrik; Naik, Rajesh R.; Frenkel, Anatoly I.; Knecht, Marc R.

    2015-07-23

    C–C coupling reactions are of great importance in the synthesis of numerous organic compounds, where Pd nanoparticle catalyzed systems represent new materials to efficiently drive these reactions. Despite their pervasive utility, the catalytic mechanism of these particle-based reactions remains highly contested. Herein we present evidence of an atom leaching mechanism for Stille coupling under aqueous conditions using peptide-capped Pd nanoparticles. EXAFS analysis revealed Pd coordination changes in the nanoparticle consistent with Pd atom abstraction, where sizing analysis by SAXS confirmed particle size changes associated with a leaching process. It is likely that recently discovered highly disordered surface Pd atoms aremore »the favored catalytic active sites and are leached during oxidative addition, resulting in smaller particles. Thus, probing the mechanism of nanoparticle-driven C–C coupling reactions through structural analyses provides fundamental information concerning these active sites and their reactivity at the atomic-scale, which can be used to improve catalytic performance to meet important sustainability goals.« less

  2. SU-E-J-70: Feasibility Study of Dynamic Arc and IMRT Treatment Plans Utilizing Vero Treatment Unit and IPlan Planning Computer for SRS/FSRT Brain Cancer Patients

    SciTech Connect (OSTI)

    Huh, S; Lee, S; Dagan, R; Malyapa, R; Mendenhall, N; Mendenhall, W; Ho, M; Hough, D; Yam, M; Li, Z

    2014-06-01

    Purpose: To investigate the feasibility of utilizing Dynamic Arc (DA) and IMRT with 5mm MLC leaf of VERO treatment unit for SRS/FSRT brain cancer patients with non-invasive stereotactic treatments. The DA and IMRT plans using the VERO unit (BrainLab Inc, USA) are compared with cone-based planning and proton plans to evaluate their dosimetric advantages. Methods: The Vero treatment has unique features like no rotational or translational movements of the table during treatments, Dynamic Arc/IMRT, tracking of IR markers, limitation of Ring rotation. Accuracies of the image fusions using CBCT, orthogonal x-rays, and CT are evaluated less than ? 0.7mm with a custom-made target phantom with 18 hidden targets. 1mm margin is given to GTV to determine PTV for planning constraints considering all the uncertainties of planning computer and mechanical uncertainties of the treatment unit. Also, double-scattering proton plans with 6F to 9F beams and typical clinical parameters, multiple isocenter plans with 6 to 21 isocenters, and DA/IMRT plans are evaluated to investigate the dosimetric advantages of the DA/IMRT for complex shape of targets. Results: 3 Groups of the patients are divided: (1) Group A (complex target shape), CI's are same for IMRT, and DGI of the proton plan are better by 9.5% than that of the IMRT, (2) Group B, CI of the DA plans (1.91+/?0.4) are better than cone-based plan, while DGI of the DA plan is 4.60+/?1.1 is better than cone-based plan (5.32+/?1.4), (3) Group C (small spherical targets), CI of the DA and cone-based plans are almost the same. Conclusion: For small spherical targets, cone-based plans are superior to other 2 plans: DS proton and DA plans. For complex or irregular plans, dynamic and IMRT plans are comparable to cone-based and proton plans for complex targets.

  3. Arc Position Sensing Technology

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O O D SFederal8823 Revision 02 (CRACApril JanuaryAps_notifyArc

  4. Cathodic Arc Plasma Deposition

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnical Report: Achievements ofCOMPOSITION OF VAPORS FROM BOILING NITRIC ACIDCathodic Arc

  5. Crystallinity and microstructure in Si films grown by plasma-enhanced chemical vapor deposition: A simple atomic-scale model validated by experiments

    SciTech Connect (OSTI)

    Novikov, P. L.; Le Donne, A.; Cereda, S.; Miglio, Leo; Pizzini, S.; Binetti, S.; Montalenti, F. [Dipartimento di Scienza dei Materiali and L-NESS, Universita di Milano-Bicocca, Via Cozzi 53, 20125 Milan (Italy); Rondanini, M.; Cavallotti, C. [Dipartimento di Chimica, Materiali, e Ingegneria Chimica 'G. Natta', Politecnico di Milano, Via Mancinelli 7, 20131 Milan (Italy); Chrastina, D.; Moiseev, T.; Kaenel, H. von; Isella, G. [Dipartimento di Fisica and L-NESS, Politecnico di Milano, Via Anzani 42, 22100 Como (Italy)

    2009-02-02

    A joint theoretical and experimental analysis of the crystalline fraction in nanocrystalline films grown by low-energy plasma enhanced chemical vapor deposition is presented. The effect of key growth parameters such as temperature, silane flux, and hydrogen dilution ratio is analyzed and modeled at the atomic scale, introducing an environment-dependent crystallization probability. A very good agreement between experiments and theory is found, despite the use of a single fitting parameter.

  6. Cathodic Vacuum Arc Plasma of Thallium

    E-Print Network [OSTI]

    Yushkov, Georgy Yu.; Anders, Andre

    2006-01-01

    P. J. Martin, Handbook of Vacuum Arc Science and Technology.charge state distributions of vacuum arc plasmas: The originand the broadening of vacuum-arc ion charge state

  7. Cathodic Vacuum Arc Plasma of Thallium

    E-Print Network [OSTI]

    Yushkov, Georgy Yu.; Anders, Andre

    2006-01-01

    distributions of vacuum arc plasmas: The origin of species,"spectrum for thallium arc plasma, as measured for 400 A,and thallium vacuum arc plasmas. For comparison, the data

  8. Arc fault detection system

    DOE Patents [OSTI]

    Jha, Kamal N. (Bethel Park, PA)

    1999-01-01

    An arc fault detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings located in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn opens an upstream circuit breaker located between the switchboard and a power supply to remove the supply of power to the switchboard.

  9. Arc fault detection system

    DOE Patents [OSTI]

    Jha, K.N.

    1999-05-18

    An arc fault detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings located in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn opens an upstream circuit breaker located between the switchboard and a power supply to remove the supply of power to the switchboard. 1 fig.

  10. Hydrologic Modeling with Arc Hydro Tools 1 Copyright 2007 ESRI. All rights reserved. Arc Hydro

    E-Print Network [OSTI]

    Slatton, Clint

    Hydrologic Modeling with Arc Hydro Tools 1 Copyright © 2007 ESRI. All rights reserved. Arc Hydro Arc Hydro: GIS in Water Resources Seminar/Workshop Gainesville, Florida ­ November 15, 2007 Christine Dartiguenave, ESRI inc. cdartiguenave@esri.com #12;Hydrologic Modeling with Arc Hydro Tools 2 2Arc Hydro

  11. Percussive arc welding apparatus

    DOE Patents [OSTI]

    Hollar, Jr., Donald L. (Overland Park, KS)

    2002-01-01

    A percussive arc welding apparatus includes a generally cylindrical actuator body having front and rear end portions and defining an internal recess. The front end of the body includes an opening. A solenoid assembly is provided in the rear end portion in the internal recess of the body, and an actuator shaft assembly is provided in the front end portion in the internal recess of the actuator body. The actuator shaft assembly includes a generally cylindrical actuator block having first and second end portions, and an actuator shaft having a front end extending through the opening in the actuator body, and the rear end connected to the first end portion of the actuator block. The second end portion of the actuator block is in operational engagement with the solenoid shaft by a non-rigid connection to reduce the adverse rebound effects of the actuator shaft. A generally transversely extending pin is rigidly secured to the rear end of the shaft. One end of the pin is received in a slot in the nose housing sleeve to prevent rotation of the actuator shaft during operation of the apparatus.

  12. Non-Equilibrium Modeling of Arc Plasma Torches

    E-Print Network [OSTI]

    Trelles, J P; Heberlein, J V R

    2013-01-01

    A two-temperature thermal non-equilibrium model is developed and applied to the three-dimensional and time-dependent simulation of the flow inside a DC arc plasma torch. A detailed comparison of the results of the non-equilibrium model with those of an equilibrium model is presented. The fluid and electromagnetic equations in both models are approximated numerically in a fully-coupled approach by a variational multi-scale finite element method. In contrast to the equilibrium model, the non-equilibrium model did not need a separate reattachment model to produce an arc reattachment process and to limit the magnitude of the total voltage drop and arc length. The non-equilibrium results show large non-equilibrium regions in the plasma - cold-flow interaction region and close to the anode surface. Marked differences in the arc dynamics, especially in the arc reattachment process, and in the magnitudes of the total voltage drop and outlet temperatures and velocities between the models are observed. The non-equilibr...

  13. Cathodic Arc Deposition of Copper Oxide Thin Films

    E-Print Network [OSTI]

    MacGill, R.A.

    2011-01-01

    compatibility. A cathodic arc plasma source with a copperon operating a cathodic arc plasma source with a copperdeposited using a cathodic arc plasma source with a copper

  14. Ion energy distribution functions of vacuum arc plasmas

    E-Print Network [OSTI]

    Byon, Eungsun; Anders, Andre

    2002-01-01

    functions of vacuum arc plasmas Eungsun Byon and Andréfunctions of vacuum arc plasmas Eungsun Byon and Andréenergies of vacuum arc plasmas 1-7 because these energies

  15. The fractal nature of vacuum arc cathode spots

    E-Print Network [OSTI]

    Anders, Andre

    2005-01-01

    functions of vacuum arc plasmas," J. Appl. Phys. , vol. 93,macroparticles in vacuum arc plasmas," in preparation, 2005.A. Anders, Cathodic Arc Plasma Deposition: From Fractal

  16. Cathodic Arcs: Fractal Voltage and Cohesive Energy Rule

    E-Print Network [OSTI]

    Anders, Andre; Oks, Efim M.; Gera, Yu. Yushkov

    2005-01-01

    Applications of Vacuum-Arc-Produced Plasma, Ion and Electronparameters of cathodic arc plasma, many researches decidedof a coaxial cathodic arc plasma source, and analyzing the

  17. Physics of arcing, and implications to sputter deposition

    E-Print Network [OSTI]

    Anders, Andre

    2005-01-01

    A. Anders, Cathodic Arc Plasma Deposition: From FractalApplications of Vacuum-Arc-Produced Plasma, Ion and Electronstandard) textbooks on plasmas [1], arcs are introduced as

  18. NEUTRAL-BEAM PLASMA SOURCE METAL-ARC PROTECTION CIRCUIT

    E-Print Network [OSTI]

    deVries, G.J.

    2010-01-01

    e r . METAL ARCS IN PLASMAS Metal-arcs in plasma sources are1981 NEUTRAL-BEAM PLASMA SOURCE METAL-ARC PROTECTION CIRCUIT48 NEUTRAL-BEAM PLASMA SOURCE METAL-ARC PROTECTION CIRCUIT*

  19. Reducing ion beam noise of vacuum arc ion sources

    E-Print Network [OSTI]

    Anders, Andre; Hollinger, Ralph

    2001-01-01

    in the expanding vacuum arc plasma and operating in the ion3 Schematic of the vacuum arc plasma generator (arc cathodeUnfortunately, vacuum arc plasmas are rapidly fluctuating

  20. Using Arc Marine in ArcGIS 10 Tutorial for Beginners

    E-Print Network [OSTI]

    Wright, Dawn Jeannine

    Using Arc Marine in ArcGIS 10 Tutorial for Beginners Introduction Arc Marine (or the ArcGIS Marine Data Model - MDM), is a geodatabase model tailored specifically for the marine GIS community. Created by researchers from Oregon State University, Duke

  1. The nature of fluctuations in a double arc argon-nitrogen plasma jet

    SciTech Connect (OSTI)

    Tu Xin; Yan Jianhua; Yu Liang; Cen, Kefa; Cheron, Bruno

    2007-09-24

    The dynamic behavior of the double arc argon-nitrogen plasma jet is investigated by combined means of the fast Fourier transform, correlation function, and Wigner distribution. The restrike mode is identified as the fluctuation behavior in an argon-nitrogen plasma jet. The Fourier spectra exhibit two characteristic frequencies of 150 Hz and 4.1 kHz, which indicates that the nature of fluctuations in the double arc argon-nitrogen plasma can be ascribed to the power supply undulation and both arc roots motion on the anode channels. It is further found that the double anode torch could inhibit and reduce the restrike phenomenon.

  2. Characterization of arcs in frequency domain

    SciTech Connect (OSTI)

    D'Inca, R.; Siegl, G.; Faugel, H.; Braun, F.; Eckert, B.; Bobkov, V.; El Khaldi, M.; Noterdaeme, J.-M.

    2009-11-26

    Arc detection systems are developed for ICRH on ITER to prevent arcs from damaging the RF components. One of the detectors, the Sub-Harmonic Arc Detector (SHAD) is based on the detection of the frequencies emitted in the MHz range by arcs [R1]. To ensure the high level of reliability required for this safety system, it is necessary to demonstrate that these frequencies present a signal with a Signal to Noise Ratio high enough to be detected under the wide range of operational conditions (frequency, power, configuration) and for the different types of arcs that can appear in the feeding lines and on the antennas (vacuum arc, glow discharge, multipactor-induced discharge). For each type of arc, we analyze the evolution of the frequency spectrum relative to the evolution of other electrical parameters (reflected power, voltage)

  3. Filters for cathodic arc plasmas

    DOE Patents [OSTI]

    Anders, Andre (Albany, CA); MacGill, Robert A. (Richmond, CA); Bilek, Marcela M. M. (Engadine, AU); Brown, Ian G. (Berkeley, CA)

    2002-01-01

    Cathodic arc plasmas are contaminated with macroparticles. A variety of magnetic plasma filters has been used with various success in removing the macroparticles from the plasma. An open-architecture, bent solenoid filter, with additional field coils at the filter entrance and exit, improves macroparticle filtering. In particular, a double-bent filter that is twisted out of plane forms a very compact and efficient filter. The coil turns further have a flat cross-section to promote macroparticle reflection out of the filter volume. An output conditioning system formed of an expander coil, a straightener coil, and a homogenizer, may be used with the magnetic filter for expanding the filtered plasma beam to cover a larger area of the target. A cathodic arc plasma deposition system using this filter can be used for the deposition of ultrathin amorphous hard carbon (a-C) films for the magnetic storage industry.

  4. Origin of static friction and its relationship to adhesion at the atomic scale Qing Zhang,1 Yue Qi,2 Louis G. Hector, Jr.,2 Tahir Cagin,1 and William A. Goddard III1

    E-Print Network [OSTI]

    Goddard III, William A.

    Origin of static friction and its relationship to adhesion at the atomic scale Qing Zhang,1 Yue Qi, we study the relationship between adhesion and static friction. The work of separation, which smooth and rough Al/Al interfaces. These values are compared with the predicted static friction stress

  5. Characterization of an atmospheric double arc argon-nitrogen plasma source

    SciTech Connect (OSTI)

    Tu, X.; Cheron, B. G.; Yan, J. H.; Yu, L.; Cen, K. F.

    2008-05-15

    In the framework of studies devoted to hazardous waste destruction, an original dc double anode plasma torch has been designed and tested, which produces an elongated, weak fluctuation and reproducible plasma jet at atmospheric pressure. The arc instabilities and dynamic behavior of the double arc argon-nitrogen plasma jet are investigated through the oscillations of electrical signals by combined means of fast Fourier transform and Wigner distribution. In our experiment, the restrike mode is identified as the typical fluctuation behavior in an argon-nitrogen plasma jet. The Fourier spectra and Wigner distributions exhibit two characteristic frequencies of 150 Hz and 4.1 kHz, which reveals that the nature of fluctuations in the double arc argon-nitrogen plasma can be ascribed to the undulation of the power supply and both arc roots motion on the anode channels. In addition, the microscopic properties of the plasma jet inside and outside the arc chamber are investigated by means of optical emission spectroscopy, which yields excitation, electronic, rotational, and vibrational temperatures, as well as the electron number density. The results allow us to examine the validity criteria of a local thermodynamic equilibrium (LTE) state in the plasma arc. The measured electron densities are in good agreement with those calculated from the LTE model, which indicates that the atmospheric double arc argon-nitrogen plasma in the core region is close to the LTE state under our experimental conditions.

  6. Matched Optics of Muon RLA and Non-Scaling FFAG ARCS

    SciTech Connect (OSTI)

    V.S. Morozov, S.A. Bogacz, Y. Roblin, K.B. Beard, D. Trbojevic

    2011-03-01

    Recirculating Linear Accelerators (RLA) are an efficient way of accelerating short-lived muons to multi-GeV energies required for Neutrino Factories and TeV energies required for Muon Colliders. To reduce the number of required return arcs, we employ a Non-Scaling Fixed-Field Alternating-Gradient (NS-FFAG) arc lattice design. We present a complete linear optics design of a muon RLA with two-pass linear NS-FFAG droplet return arcs. The arcs are composed of symmetric cells with each cell designed using combined function magnets with dipole and quadrupole magnetic field components so that the cell is achromatic and has zero initial and final periodic orbit offsets for both passes’ energies. Matching to the linac is accomplished by adjusting linac quadrupole strengths so that the linac optics on each pass is matched to the arc optics. We adjust the difference of the path lengths and therefore of the times of flight of the two momenta in each arc to ensure proper synchronization with the linac. We investigate the dynamic aperture and momentum acceptance of the arcs.

  7. Effects of current on droplet generation and arc plasma in gas metal arc welding

    SciTech Connect (OSTI)

    Hu, J.; Tsai, H. L.

    2006-09-01

    In gas metal arc welding (GMAW), a technology using pulsed currents has been employed to achieve the one-droplet-per-pulse (ODPP) metal transfer mode with the advantages of low average currents, a stable and controllable droplet generation, and reduced spatter. In this paper, a comprehensive model was developed to study the effects of different current profiles on the droplet formation, plasma generation, metal transfer, and weld pool dynamics in GMAW. Five types of welding currents were studied, including two constant currents and three wave form currents. In each type, the transient temperature and velocity distributions of the arc plasma and the molten metal, and the shapes of the droplet and the weld pool were calculated. The results showed that a higher current generates smaller droplets, higher droplet frequency, and higher electromagnetic force that becomes the dominant factor detaching the droplet from the electrode tip. The model has demonstrated that a stable ODPP metal transfer mode can be achieved by choosing a current with proper wave form for given welding conditions.

  8. Charge state dependence of cathodic vacuum arc ion energy and velocity distributions

    E-Print Network [OSTI]

    Rosen, Johanna; Schneider, Jochen M.; Anders, Andre

    2006-01-01

    velocity in vacuum arc plasmas by arc current perturbationin aluminum vacuum arc plasma. We show that the conflictingdistinguished. Cathodic vacuum arc plasma is well known to

  9. Plasma arc torch with coaxial wire feed

    DOE Patents [OSTI]

    Hooper, Frederick M (Albuquerque, NM)

    2002-01-01

    A plasma arc welding apparatus having a coaxial wire feed. The apparatus includes a plasma arc welding torch, a wire guide disposed coaxially inside of the plasma arc welding torch, and a hollow non-consumable electrode. The coaxial wire guide feeds non-electrified filler wire through the tip of the hollow non-consumable electrode during plasma arc welding. Non-electrified filler wires as small as 0.010 inches can be used. This invention allows precision control of the positioning and feeding of the filler wire during plasma arc welding. Since the non-electrified filler wire is fed coaxially through the center of the plasma arc torch's electrode and nozzle, the wire is automatically aimed at the optimum point in the weld zone. Therefore, there is no need for additional equipment to position and feed the filler wire from the side before or during welding.

  10. Magnetic-cusp, cathodic-arc source

    DOE Patents [OSTI]

    Falabella, Steven (Livermore, CA)

    1995-01-01

    A magnetic-cusp for a cathodic-arc source wherein the arc is confined to the desired cathode surface, provides a current path for electrons from the cathode to the anode, and utilizes electric and magnetic fields to guide ions from the cathode to a point of use, such as substrates to be coated. The magnetic-cusp insures arc stability by an easy magnetic path from anode to cathode, while the straight-through arrangement leads to high ion transmission.

  11. Arc Geometry and Algebra: Foliations, Moduli Spaces, String ...

    E-Print Network [OSTI]

    2012-05-02

    yields a modular operad structure on the homology level. .... 1.4.2 Elements as weighted arc families A weight function wt on an arc family ...... Figure 6. I, the identity and II, the arc family ? yielding the BV operator ..... weighted arc family obtained by scaling all weights of arcs incident to ?i of ? homoge- ..... A careful analysis.

  12. Metals purification by improved vacuum arc remelting

    DOE Patents [OSTI]

    Zanner, Frank J. (Sandia Park, NM); Williamson, Rodney L. (Albuquerque, NM); Smith, Mark F. (Albuquerque, NM)

    1994-12-13

    The invention relates to improved apparatuses and methods for remelting metal alloys in furnaces, particularly consumable electrode vacuum arc furnaces. Excited reactive gas is injected into a stationary furnace arc zone, thus accelerating the reduction reactions which purify the metal being melted. Additionally, a cooled condensation surface is disposed within the furnace to reduce the partial pressure of water in the furnace, which also fosters the reduction reactions which result in a purer produced ingot. Methods and means are provided for maintaining the stationary arc zone, thereby reducing the opportunity for contaminants evaporated from the arc zone to be reintroduced into the produced ingot.

  13. Gamma-Normal Probability Distribution Arc Length

    E-Print Network [OSTI]

    Hesam

    2014-11-04

    ... Engineering, Mazandaran University of Science and Technology, Babol, Iran ... the arcs are assumed to represent transportation time or cost rather than the ...

  14. Miniaturized cathodic arc plasma source

    DOE Patents [OSTI]

    Anders, Andre (Albany, CA); MacGill, Robert A. (Richmond, CA)

    2003-04-15

    A cathodic arc plasma source has an anode formed of a plurality of spaced baffles which extend beyond the active cathode surface of the cathode. With the open baffle structure of the anode, most macroparticles pass through the gaps between the baffles and reflect off the baffles out of the plasma stream that enters a filter. Thus the anode not only has an electrical function but serves as a prefilter. The cathode has a small diameter, e.g. a rod of about 1/4 inch (6.25 mm) diameter. Thus the plasma source output is well localized, even with cathode spot movement which is limited in area, so that it effectively couples into a miniaturized filter. With a small area cathode, the material eroded from the cathode needs to be replaced to maintain plasma production. Therefore, the source includes a cathode advancement or feed mechanism coupled to cathode rod. The cathode also requires a cooling mechanism. The movable cathode rod is housed in a cooled metal shield or tube which serves as both a current conductor, thus reducing ohmic heat produced in the cathode, and as the heat sink for heat generated at or near the cathode. Cooling of the cathode housing tube is done by contact with coolant at a place remote from the active cathode surface. The source is operated in pulsed mode at relatively high currents, about 1 kA. The high arc current can also be used to operate the magnetic filter. A cathodic arc plasma deposition system using this source can be used for the deposition of ultrathin amorphous hard carbon (a-C) films for the magnetic storage industry.

  15. Groundwater Modeling in ArcView: by integrating ArcView, MODFLOW and

    E-Print Network [OSTI]

    Sengupta, Raja

    Groundwater Modeling in ArcView: by integrating ArcView, MODFLOW and MODPATH Abstract Modeling. This paper addresses groundwater modeling which is one of the many entities in environmental modeling in ArcView 3.2a. The objective was to create an integrated system where a user could do groundwater

  16. Asymmetric injection of cathodic arc plasma into a macroparticle filter

    E-Print Network [OSTI]

    Anders, Andre; MacGill, Robert A.

    2004-01-01

    setup. The cathodic arc plasma source is flange-mounted andfirewall" twist filter arc plasma source F IG. 1 Current (A)Injection of Cathodic Arc Plasma into a Macroparticle Filter

  17. Filtered cathodic arc deposition with ion-species-selective bias

    E-Print Network [OSTI]

    Anders, Andre; Pasaja, Nitisak; Sansongsiri, Sakon; Lim, Sunnie H.N.

    2006-01-01

    Photograph of a cathodic arc plasma source with two cathodesof ions of cathodic arc plasmas. The selection was made forAbstract A dual-cathode arc plasma source was combined with

  18. MULTIPLY STRIPPED ION GENERATION IN THE METAL VAPOR VACUUM ARC

    E-Print Network [OSTI]

    Brown, I.G.

    2010-01-01

    the metal vapor vacuum arc plasma discharge. A new kind offrom a metal vapor vacuum arc plasma has been used to obtaindrives the vacuum arc plasma is created. The fundamental

  19. Measurement of total ion current from vacuum arc plasma sources

    E-Print Network [OSTI]

    Oks, Efim M.; Savkin, Konstantin P.; Yushkov, Georgiu Yu.; Nikolaev, Alexey G.; Anders, A.; Brown, Ian G.

    2005-01-01

    A. Anders, Cathodic Arc Plasma Deposition: From Fractalion current from vacuum arc plasma sources E. M. Oks, K. P.ion current from vacuum arc plasma sources E. M. Oks, K. P.

  20. Vacuum Arc Ion Sources: Recent Developments and Applications

    E-Print Network [OSTI]

    Brown, Ian; Oks, Efim

    2005-01-01

    charge states in vacuum arc plasmas using a 'current spike'of pulsed vacuum arc plasmas in strong magnetic fields",of electrons in vacuum arc plasmas", Rev. Sci. Instrum. ,

  1. Measurement of total ion flux in vacuum Arc discharges

    E-Print Network [OSTI]

    Anders, Andre; Oks, Efim M.; Yushkov, Georgy Yu.; Brown, Ian G.

    2004-01-01

    in high current vacuum arc plasma in a magnetic field," IEEEdistributions of vacuum arc plasmas: The origin of species,"high-current vacuum arc plasmas," IEEE Trans. Plasma Sci. ,

  2. Purification of tantalum by plasma arc melting

    DOE Patents [OSTI]

    Dunn, Paul S. (Santa Fe, NM); Korzekwa, Deniece R. (Los Alamos, NM)

    1999-01-01

    Purification of tantalum by plasma arc melting. The level of oxygen and carbon impurities in tantalum was reduced by plasma arc melting the tantalum using a flowing plasma gas generated from a gas mixture of helium and hydrogen. The flowing plasma gases of the present invention were found to be superior to other known flowing plasma gases used for this purpose.

  3. Low voltage arc formation in railguns

    DOE Patents [OSTI]

    Hawke, Ronald S. (Livermore, CA)

    1987-01-01

    A low voltage plasma arc is first established across the rails behind the projectile by switching a low voltage high current source across the rails to establish a plasma arc by vaporizing a fuse mounted on the back of the projectile, maintaining the voltage across the rails below the railgun breakdown voltage to prevent arc formation ahead of the projectile. After the plasma arc has been formed behind the projectile a discriminator switches the full energy bank across the rails to accelerate the projectile. A gas gun injector may be utilized to inject a projectile into the breech of a railgun. The invention permits the use of a gas gun or gun powder injector and an evacuated barrel without the risk of spurious arc formation in front of the projectile.

  4. Low voltage arc formation in railguns

    DOE Patents [OSTI]

    Hawke, R.S.

    1985-08-05

    A low voltage plasma arc is first established across the rails behind the projectile by switching a low voltage high current source across the rails to establish a plasma arc by vaporizing a fuse mounted on the back of the projectile, maintaining the voltage across the rails below the railgun breakdown voltage to prevent arc formation ahead of the projectile. After the plasma arc has been formed behind the projectile a discriminator switches the full energy bank across the rails to accelerate the projectile. A gas gun injector may be utilized to inject a projectile into the breech of a railgun. The invention permits the use of a gas gun or gun powder injector and an evacuated barrel without the risk of spurious arc formation in front of the projectile.

  5. Low voltage arc formation in railguns

    DOE Patents [OSTI]

    Hawke, R.S.

    1987-11-17

    A low voltage plasma arc is first established across the rails behind the projectile by switching a low voltage high current source across the rails to establish a plasma arc by vaporizing a fuse mounted on the back of the projectile, maintaining the voltage across the rails below the railgun breakdown voltage to prevent arc formation ahead of the projectile. After the plasma arc has been formed behind the projectile a discriminator switches the full energy bank across the rails to accelerate the projectile. A gas gun injector may be utilized to inject a projectile into the breech of a railgun. The invention permits the use of a gas gun or gun powder injector and an evacuated barrel without the risk of spurious arc formation in front of the projectile. 2 figs.

  6. Nitrogen Control in Electric Arc Furnace Steelmaking by Direct...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Nitrogen Control in Electric Arc Furnace Steelmaking by Direct Reduced Iron Fines Injection Nitrogen Control in Electric Arc Furnace Steelmaking by Direct Reduced Iron Fines...

  7. Boron nitride ablation studies in arc jet facilities (Conference...

    Office of Scientific and Technical Information (OSTI)

    Boron nitride ablation studies in arc jet facilities Citation Details In-Document Search Title: Boron nitride ablation studies in arc jet facilities You are accessing a document...

  8. True atomic-scale imaging of a spinel Li{sub 4}Ti{sub 5}O{sub 12}(111) surface in aqueous solution by frequency-modulation atomic force microscopy

    SciTech Connect (OSTI)

    Kitta, Mitsunori, E-mail: m-kitta@aist.go.jp; Kohyama, Masanori [Research Institute for Ubiquitous Energy Devices, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan); Onishi, Hiroshi [Department of Chemistry, Graduate School of Science, Kobe University 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan)

    2014-09-15

    Spinel-type lithium titanium oxide (LTO; Li{sub 4}Ti{sub 5}O{sub 12}) is a negative electrode material for lithium-ion batteries. Revealing the atomic-scale surface structure of LTO in liquid is highly necessary to investigate its surface properties in practical environments. Here, we reveal an atomic-scale image of the LTO(111) surface in LiCl aqueous solution using frequency-modulation atomic force microscopy. Atomically flat terraces and single steps having heights of multiples of 0.5?nm were observed in the aqueous solution. Hexagonal bright spots separated by 0.6?nm were also observed on the flat terrace part, corresponding to the atomistic contrast observed in the ultrahigh vacuum condition, which suggests that the basic atomic structure of the LTO(111) surface is retained without dramatic reconstruction even in the aqueous solution.

  9. Magnetic-cusp, cathodic-arc source

    DOE Patents [OSTI]

    Falabella, S.

    1995-11-21

    A magnetic-cusp for a cathodic-arc source wherein the arc is confined to the desired cathode surface, provides a current path for electrons from the cathode to the anode, and utilizes electric and magnetic fields to guide ions from the cathode to a point of use, such as substrates to be coated. The magnetic-cusp insures arc stability by an easy magnetic path from anode to cathode, while the straight-through arrangement leads to high ion transmission. 3 figs.

  10. Linking ArcView 3.0TM and XGobi: Insight Behind the Front End

    E-Print Network [OSTI]

    Symanzik, Jürgen

    of a bidirectional link between the Geographic Information System (GIS) ArcView 3.0TM and the interactive dynamic Information Systems (GISs) are used extensively for examining spa- tial data but, traditionally, they have few tools necessary for displaying geographic information. The lack of ex- ploratory tools in a GIS

  11. ARC Collaborative Research Seminar Series September 16th, Thursday (1:30-3:00pm)

    E-Print Network [OSTI]

    Papalambros, Panos

    Alternative Energy/Power Systems Anna Stefanopoulou and Jeff Stein, University of Michigan (click here, GM Room ARC Collaborative Research Seminar Series #12;Presented by Thrust Area 2: Modeling Vehicle.Professor, U. of Michigan Overview of Bio-dynamic Modeling of Vehicle-Operator Systems Wade Allen, Technical

  12. Motion characteristics of long ac arcs in atmospheric air

    SciTech Connect (OSTI)

    Gu Shanqiang; He Jinliang; Zeng Rong; Zhang Bo; Xu Guozheng; Chen Weijiang

    2007-01-29

    Experiments on the motion of long alternating current arcs in atmospheric air show that the anode and cathode arc roots have different motion characteristics because of different formation mechanisms. During a half cycle of the arc current, the anode arc root moves towards the direction of magnetic force and occasionally has a jumping motion, while the cathode arc root moves sufficiently slow to consider it stationary and hardly has any jump. The arc column has a complex shape and moves under the drive of the magnetic force and is also quickened by the lower arc root.

  13. Detection of arcs in automotive electrical systems

    E-Print Network [OSTI]

    Mishrikey, Matthew David

    2005-01-01

    At the present time, there is no established method for the detection of DC electric arcing. This is a concern for forthcoming advanced automotive electrical systems which consist of higher DC electric power bus voltages, ...

  14. Hawley ArcGIS Desktop III: GIS Workflows and Analysis Page 1 ArcGIS Desktop III

    E-Print Network [OSTI]

    Bier, Martin

    Hawley ArcGIS Desktop III: GIS Workflows and Analysis Page 1 ArcGIS Desktop III: GIS Workflows and Analysis Overview This 2-day course builds on the skills and knowledge taught in ArcGIS Desktop II: Tools a challenging analysis project. Audience This course is for experienced ArcGIS users who want to learn more

  15. ArcGIS Explorer Online Extended Use Quick Guide ArcGIS Explorer Online--GIS for Everyone

    E-Print Network [OSTI]

    Wright, Dawn Jeannine

    ArcGIS Explorer Online Extended Use Quick Guide ArcGIS Explorer Online--GIS for Everyone Creating notes, photo links, and presentations ArcGIS Explorer Online (AGXO) is a browser-based GIS viewer, perform queries and create presentations. This quick guide is an extension of the Introduction to ArcGIS

  16. Klystron Gun Arcing and Modulator Protection

    SciTech Connect (OSTI)

    Gold, S

    2004-05-04

    The demand for 500 kV and 265 amperes peak to power an X-Band klystron brings up protection issues for klystron faults and the energy dumped into the arc from the modulator. This situation is made worse when more than one klystron will be driven from a single modulator, such as the existing schemes for running two and eight klystrons. High power pulsed klystrons have traditionally be powered by line type modulators which match the driving impedance with the load impedance and therefore current limit at twice the operating current. Multiple klystrons have the added problems of a lower modulator source impedance and added stray capacitance, which converts into appreciable energy at high voltages like 500kV. SLAC has measured the energy dumped into klystron arcs in a single and dual klystron configuration at the 400 to 450 kV level and found interesting characteristics in the arc formation. The author will present measured data from klystron arcs powered from line-type modulators in several configurations. The questions arise as to how the newly designed solid-state modulators, running multiple tubes, will react to a klystron arc and how much energy will be dumped into the arc.

  17. Ion source with improved primary arc collimation

    DOE Patents [OSTI]

    Dagenhart, William K. (Oak Ridge, TN)

    1985-01-01

    An improved negative ion source is provided in which a self-biasing, molybdenum collimator is used to define the primary electron stream arc discharge from a filament operated at a negative potential. The collimator is located between the anode and the filament. It is electrically connected to the anode by means of an appropriate size resistor such that the collimator is biased at essentially the filament voltage during operation. Initially, the full arc voltage appears across the filament to collimator until the arc discharge strikes. Then the collimator biases itself to essentially filament potential due to current flow through the resistor thus defining the primary electron stream without intercepting any appreciable arc power. The collimator aperture is slightly smaller than the anode aperture to shield the anode from the arc power, thereby preventing the exposure of the anode to the full arc power which, in the past, has caused overheating and erosion of the anode collimator during extended time pulsed-beam operation of the source. With the self-biasing collimator of this invention, the ion source may be operated from short pulse periods to steady-state without destroying the anode.

  18. Heat flux characteristics in an atmospheric double arc argon plasma jet

    SciTech Connect (OSTI)

    Tu Xin; Yu Liang; Yan Jianhua; Cen Kefa; Cheron, Bruno

    2008-10-13

    In this study, the axial evolution of heat flux excited by a double arc argon plasma jet impinging on a flat plate is determined, while the nonstationary behavior of the heat flux is investigated by combined means of the fast Fourier transform, Wigner distribution, and short-time Fourier transform. Two frequency groups (<1 and 2-10 kHz) are identified in both the Fourier spectrum and the time-frequency distributions, which suggest that the nature of fluctuations in the heat flux is strongly associated with the dynamic behavior of the plasma arc and the engulfment of ambient air into different plasma jet regions.

  19. ABSTRACT. Keyhole plasma arc welding is a unique arc welding process for deep

    E-Print Network [OSTI]

    Zhang, YuMing

    ABSTRACT. Keyhole plasma arc welding is a unique arc welding process for deep penetration. To ensure the quality of the welds, the presence of the keyhole is crit- ical. Understanding of the keyhole will certainly benefit the improvement of the process and weld quality. Currently, the size of the keyhole

  20. Three-dimensional model and simulation of vacuum arcs under axial magnetic fields

    SciTech Connect (OSTI)

    Wang Lijun; Jia Shenli; Zhou Xin; Wang Haijing; Shi Zongqian

    2012-01-15

    In this paper, a three-dimensional (3d) magneto-hydro-dynamic (MHD) model of axial magnetic field vacuum arcs (AMFVAs) is established. Based on this model, AMFVAs are simulated and analyzed. Three-dimensional spatial distributions of many important plasma parameters and electric characteristics in AMFVAs can be obtained, such as ion number density, ion temperature, electron temperature, plasma pressure, current densities along different directions (x, y, and z), ion velocities along different directions, electric fields strength along different directions, and so on. Simulation results show that there exist significant spiral-shaped rotational phenomena in the AMFVAs, this kind of rotational phenomenon also can be verified by the many related experiments (AMFVAs photographs, especially for stronger AMF strength). For current simulation results of AMFVAs, the maximal rotational velocity at anode side is about 1100 m/s. Radial electric field is increased from arc center to arc edge; axial electric field is decreased from cathode side to anode side. Radial electric field at arc edge can be larger than axial electric field. Azimuthal electric field in most regions is much smaller than radial and axial electric field, but it can reach about 1.19 kV/m. Radial magnetic field is the smallest one compared with other components, it reaches to maximum value at the position near to anode, it can influence arc characteristics.

  1. Vacuum Arc Melting Unit Arc Melting is used for melting metals typically to form alloys. Heating is via an electric arc struck

    E-Print Network [OSTI]

    Subramaniam, Anandh

    Vacuum Arc Melting Unit Arc Melting is used for melting metals­ typically to form alloys. Heating unit is used as a power source. Heat generated by the electric arc struck between the electrode unit. The vacuum unit with rotary and diffusion pumps can attain a vacuum of 106 m bar. The cold

  2. Charge state and time resolved plasma composition of a pulsed zirconium arc in a nitrogen environment

    E-Print Network [OSTI]

    Rosen, Johanna; Anders, Andre; Hultman, Lars; Schneider, Jochen M.

    2004-01-01

    of a pulsed cathodic arc plasma was investigated atof a growing film in arc plasma deposition. In the presencea titanium cathodic arc plasma at varying nitrogen pressure,

  3. The evolution of ion charge states in cathodic vacuum arc plasmas: a review

    E-Print Network [OSTI]

    Anders, Andre

    2013-01-01

    in metal vapor vacuum arc plasmas and ion sources," Plasmathe separation of cathodic arc plasma and macroparticles incharge states in vacuum arc plasmas in a magnetic field,"

  4. Ultrathin diamond-like carbon films deposited by filtered carbon vacuum arcs

    E-Print Network [OSTI]

    Anders, Andre; Fong, Walton; Kulkarni, Ashok; Ryan, Francis W.; Bhatia, C. Singh

    2001-01-01

    Ion velocities in vacuum arc plasmas,” J. Appl. Phys. , vol.Brown, “Transport of vacuum arc plasma through straight anda filtered cathodic arc,” Plasma Sources Sci. Technol. , pp.

  5. Material and time dependence of the voltage noise generated by cathodic vacuum arcs

    E-Print Network [OSTI]

    Rosen, Johanna; Anders, Andre

    2005-01-01

    associated with plasma production and arc impedance, it wasbecause it is known that arc plasma parameters have almost “Applications of Vacuum-Arc-Produced Plasma, Ion and Electron

  6. Ion source with improved primary arc collimation

    DOE Patents [OSTI]

    Dagenhart, W.K.

    1983-12-16

    An improved negative ion source is provided in which a self-biasing, molybdenum collimator is used to define the primary electron stream arc discharge from a filament operated at a negative potential. The collimator is located between the anode and the filament. It is electrically connected to the anode by means of an appropriate size resistor such that the collimator is biased at essentially the filament voltage during operation. Initially, the full arc voltage appears across the filament to collimator until the arc discharge strikes. Then the collimator biases itself to essentially filament potential due to current flow through the resistor thus defining the primary electron stream without intercepting any appreciable arc power. The collimator aperture is slightly smaller than the anode aperture to shield the anode from the arc power which, in the past, has caused overheating and erosion of the anode collimator during extended time pulsed-beam operation of the source. With the self-biasing collimator of this invention, the ion source may be operated from short pulse periods to steady-state without destroying the anode.

  7. Dynamic Transmission Electron Microscopy

    SciTech Connect (OSTI)

    Evans, James E.; Jungjohann, K. L.; Browning, Nigel D.

    2012-10-12

    Dynamic transmission electron microscopy (DTEM) combines the benefits of high spatial resolution electron microscopy with the high temporal resolution of ultrafast lasers. The incorporation of these two components into a single instrument provides a perfect platform for in situ observations of material processes. However, previous DTEM applications have focused on observing structural changes occurring in samples exposed to high vacuum. Therefore, in order to expand the pump-probe experimental regime to more natural environmental conditions, in situ gas and liquid chambers must be coupled with Dynamic TEM. This chapter describes the current and future applications of in situ liquid DTEM to permit time-resolved atomic scale observations in an aqueous environment, Although this chapter focuses mostly on in situ liquid imaging, the same research potential exists for in situ gas experiments and the successful integration of these techniques promises new insights for understanding nanoparticle, catalyst and biological protein dynamics with unprecedented spatiotemporal resolution.

  8. Influence of a transverse magnetic field on arc root movements in a dc plasma torch: Diamagnetic effect of arc column

    SciTech Connect (OSTI)

    Kim, Keun Su

    2009-03-23

    The effect of a transverse magnetic field on the anodic arc root movement inside a dc plasma torch has been investigated. The arc voltage fluctuation, which represents the degree of the arc instability, was reduced to 28.6% of the original value and the high frequency components in the voltage signal also decreased in their magnitudes. The inherent arc instability in a dc thermal plasma torch seems to be suppressed by a diamagnetic effect of the arc column. Furthermore, the measured voltage wave forms indicated that the arc root attachment mode would be controllable by a transverse magnetic field.

  9. Ion source based on the cathodic arc

    DOE Patents [OSTI]

    Sanders, D.M.; Falabella, S.

    1994-02-01

    A cylindrically symmetric arc source to produce a ring of ions which leave the surface of the arc target radially and are reflected by electrostatic fields present in the source to a point of use, such as a part to be coated, is described. An array of electrically isolated rings positioned in the source serves the dual purpose of minimizing bouncing of macroparticles and providing electrical insulation to maximize the electric field gradients within the source. The source also includes a series of baffles which function as a filtering or trapping mechanism for any macroparticles. 3 figures.

  10. Connecting ARC/INFO and SNACTor Project Report

    E-Print Network [OSTI]

    California at Santa Barbara, University of

    Connecting ARC/INFO and SNACTor Project Report June 1991 Stuart C. Shapiro, Hans Chalupsky;Connecting ARC/INFO* and SNACTor --- Project Report1 Stuart C. Shapiro2 , Hans Chalupsky2 and Hsueh

  11. A study of vacuum arc ion velocities using a linear set of probes

    E-Print Network [OSTI]

    Hohenbild, Stefan

    2008-01-01

    method; aluminum plasma; arc current constant at 200 A.velocity in vacuum arc plasmas by arc current perturbationin the vicinity of the arc plasma source. submitted to J.

  12. Ion flux from vacuum arc cathode spots in the absence and presence of a magnetic field

    E-Print Network [OSTI]

    Anders, Andre; Yushkov, George Yu.

    2001-01-01

    velocity in vacuum arc plasmas by arc current perturbation,field increases the plasma impedance, arc burning voltage,is well-known that the vacuum arc plasma is produced at non-

  13. Modeling rf breakdown arcs II: plasma / materials interactions

    E-Print Network [OSTI]

    Insepov, Zeke; Proslier, Thomas; Mahalingam, Sudhakar; Veitzer, S

    2010-01-01

    Continuing the description of rf vacuum arcs from an earlier paper, we describe some aspects of the interaction of vacuum arcs that involve the surface. This paper describes aspects of plasma materials interactions that affect the arc and models measurement of the surface field using the Tonks-Frenkel and the spinodal electrohydrodynamic instabilities, a realistic model for the generation and evaluation of high field enhancements, unipolar arcs, creep and other effects.

  14. Poster — Thur Eve — 39: Feasibility of Commissioning HybridArc with the Delta 4 two plane diode phantom: comparisons with Gafchromic Film

    SciTech Connect (OSTI)

    Bojechko, C.; Ploquin, N.; Hudson, A.; Sayous, Y.

    2014-08-15

    HybridArc is a relatively novel radiation therapy technique which combines optimized dynamic conformai arcs (DCA) and intensity modulated radiation therapy (IMRT). HybridArc has possible dosimetry and efficiency advantages over stand alone DCA and IMRT treatments and can be readily implemented on any linac capable of DCA and IMRT, giving strong motivation to commission the modality. The Delta4 phantom (Scandidos, Uppsala, Sweden) has been used for IMRT and VMAT clinical dosimetric verification making it a candidate for HybridArc commissioning. However the HybridArc modality makes use of several non co-planar arcs which creates setup issues due to the geometry of the Delta4, resulting in possible phantom gantry collisions for plans with non-zero couch angles. An analysis was done determining the feasibility of using the Delta4 fixed at 0° couch angle compared with results obtained using Gafchromic ETB2 film (Ashland, Covington Kentucky) in an anthropomorphic phantom at the planned couch angles. A gamma index analysis of the measured and planned dose distributions was done using Delta4 and DoseLab Pro (Mobius Medical Systems, Houston Texas) software. For both arc and IMRT sub-fields there is reasonable correlation between the gamma index found from the Delta4 and Gafchromic film. All results show the feasibility of using the Delta4 for HybridArc commissioning.

  15. Costing of Joining Methods -Arc Welding Costs

    E-Print Network [OSTI]

    Colton, Jonathan S.

    Costing of Joining Methods - Arc Welding Costs ver. 1 ME 6222: Manufacturing Processes and Systems.S. Colton © GIT 2009 5 #12;LaborLabor Di t ti f ldi· Direct time of welding ­ time to produce a length of weld ­ labor rate ­ multiplication gives labor cost per length · Set-up time, etc. · Personal time

  16. Pairing, pseudogap and Fermi arcs in cuprates

    SciTech Connect (OSTI)

    Kaminski, Adam; Gu, Genda; Kondo, Takeshi; Takeuchi, Tsunehiro

    2014-04-29

    We use Angle Resolved Photoemission Spectroscopy (ARPES) to study the relationship between the pseudogap, pairing and Fermi arcs in cuprates. High quality data measured over a wide range of dopings reveals a consistent picture of Fermiology and pairing in these materials. The pseudogap is due to an ordered state that competes with superconductivity rather than preformed pairs. Pairing does occur below Tpair ~ 150K and significantly above Tc, but well below T* and the doping dependence of this temperature scale is distinct from that of the pseudogap. The d-wave gap is present below Tpair, and its interplay with strong scattering creates “artificial” Fermi arcs for Tc < T < Tpair. However, above Tpair, the pseudogap exists only at the antipodal region. This leads to presence of real, gapless Fermi arcs close to the node. The length of these arcs remains constant up to T*, where the full Fermi surface is recovered. We demonstrate that these findings resolve a number of seemingly contradictory scenarios.

  17. Remote electrical arc suppression by laser filamentation

    E-Print Network [OSTI]

    Schubert, Elise; Kasparian, Jérôme; Wolf, Jean-Pierre

    2015-01-01

    We investigate the interaction of narrow plasma channels formed in the filamentation of ultrashort laser pulses, with a DC high voltage. The laser filaments prevent electrical arcs by triggering corona that neutralize the high-voltage electrodes. This phenomenon, due to the electric field modulation and free electron release around the filament, opens new prospects to lightning and over-voltage mitigation.

  18. Pairing, pseudogap and Fermi arcs in cuprates

    SciTech Connect (OSTI)

    Kaminski, Adam [Iowa State Univ., Ames, IA (United States); Gu, Genda [Brookhaven National Lab. (BNL), Upton, NY (United States); Kondo, Takeshi [The Univ. of Tokyo, Chiba (Japan); Takeuchi, Tsunehiro [Nagoya Univ., Nagoya (Japan)

    2014-10-31

    We use Angle Resolved Photoemission Spectroscopy (ARPES) to study the relationship between the pseudogap, pairing and Fermi arcs in cuprates. High quality data measured over a wide range of dopings reveals a consistent picture of Fermiology and pairing in these materials. The pseudogap is due to an ordered state that competes with superconductivity rather than preformed pairs. Pairing does occur below Tpair ~ 150K and significantly above Tc, but well below T* and the doping dependence of this temperature scale is distinct from that of the pseudogap. The d-wave gap is present below Tpair, and its interplay with strong scattering creates “artificial” Fermi arcs for Tc < T < Tpair. However, above Tpair, the pseudogap exists only at the antipodal region. This leads to presence of real, gapless Fermi arcs close to the node. The length of these arcs remains constant up to T*, where the full Fermi surface is recovered. We demonstrate that these findings resolve a number of seemingly contradictory scenarios.

  19. Exploring the Deep... Using ArcMap

    E-Print Network [OSTI]

    Wright, Dawn Jeannine

    started Exploring the Ocean Environment Introduction #12;The ArcMap User Interface Table of Contents off the layers above that layer in the Table of Contents. Table of Contents A list of data frames of the current map file. Coordinates Displays the coordinates, in the currently-selected units, of the cursor

  20. Energy Savings in Electric Arc Furnace Melting 

    E-Print Network [OSTI]

    Lubbeck, W.

    1982-01-01

    Arc furnace melting which at one time was almost exclusively used to produce alloy steel and steel castings is now widely accepted in the industry as an efficient process to produce all types of steel and iron. Presently, about 28% of steel...

  1. Pairing, pseudogap and Fermi arcs in cuprates

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kaminski, Adam; Kondo, Takeshi; Takeuchi, Tsunehiro; Gu, Genda

    2014-04-29

    We use Angle Resolved Photoemission Spectroscopy (ARPES) to study the relationship between the pseudogap, pairing and Fermi arcs in cuprates. High quality data measured over a wide range of dopings reveals a consistent picture of Fermiology and pairing in these materials. The pseudogap is due to an ordered state that competes with superconductivity rather than preformed pairs. Pairing does occur below Tpair ~ 150K and significantly above Tc, but well below T* and the doping dependence of this temperature scale is distinct from that of the pseudogap. The d-wave gap is present below Tpair, and its interplay with strong scatteringmore »creates “artificial” Fermi arcs for Tc ? T ? Tpair. However, above Tpair, the pseudogap exists only at the antipodal region. This leads to presence of real, gapless Fermi arcs close to the node. The length of these arcs remains constant up to T*, where the full Fermi surface is recovered. As a result, we demonstrate that these findings resolve a number of seemingly contradictory scenarios.« less

  2. Theory of the arc discharge in air blast breakers

    SciTech Connect (OSTI)

    Vogel, H.F.

    1980-08-01

    The complete set of equations obtaining in the arc's length element are given. The arc length is determined when the external circuit equations are closed by an expression for the arc inductance as a function of the radius and length, in addition to our relationships for the radius and voltage gradients.

  3. Driven Motion and Instability of an Atmospheric Pressure Arc

    E-Print Network [OSTI]

    of equilibrium and stability of such arcs, an experimental arc furnace is constructed and operated in air. Applicability of the results of the thesis to an industrial steelmaking furnace is considered. iv #12; Dedicated am very thankful to Lane Roquemore for helping get the Arc Furnace o# the ground and for his

  4. PYROLYSIS OF METHANE IN A SUPERSONIC, ARC-HEATED FLOW

    E-Print Network [OSTI]

    Texas at Arlington, University of

    1 PYROLYSIS OF METHANE IN A SUPERSONIC, ARC-HEATED FLOW F.K. Lu,* C.M. Roseberry, J.M. Meyers and D arc pyrolysis of methane at supersonic conditions, representative of conditions in the reformer location of an aibreathing hypersonic vehicle. The rationale for arc pyrolysis is provided. Major

  5. INSTRUCTIONS FOR USING ARCVIEW ArcViewsoftwareisavailableintheUTSLab,

    E-Print Network [OSTI]

    Thompson, Michael

    SciencesBuilding,Room241and in Mills Library, Gateway Data/GIS Lab, Room 111A. Arc the ArcView GIS icon. If you are in the Map Collection or the Gateway Data/GIS Lab: Before starting copy of the data files.) Select Start. Select Programs. Select ArcView GIS. If your first screen does

  6. Aplicaciones de Arc GISAplicaciones de Arc GIS en Recursos de Aguaen Recursos de Agua

    E-Print Network [OSTI]

    Gilbes, Fernando

    Aplicaciones de Arc GISAplicaciones de Arc GIS en Recursos de Aguaen Recursos de Agua Alejandra 14: 440 personas/km2 vrs India y Japón 338vrs India y Japón 338 perper/km2./km2. El uso del agua se ha incrementado un 1.6% de 1970 aEl uso del agua se ha incrementado un 1.6% de 1970 a 1995 con 2

  7. Magnetized Cascade Arc Source forMagnetized Cascade Arc Source for Ionization and Fuelling in TCSUIonization and Fuelling in TCSU

    E-Print Network [OSTI]

    Washington at Seattle, University of

    , the arc source can also be run during FRC sustainment to provide steady state plasma fuelling. The deuterium plasma produced by the arc source is tied to the external axial magnetic field lines, providing and is used for initial breakdown and arc sustainment. Plasma densities of 1020 m-3 and electron temperatures

  8. Characteristic of a triple-cathode vacuum arc plasma source

    SciTech Connect (OSTI)

    Xiang, W.; Li, M.; Chen, L.

    2012-02-15

    In order to generate a better ion beam, a triple-cathode vacuum arc plasma source has been developed. Three plasma generators in the vacuum arc plasma source are equally located on a circle. Each generator initiated by means of a high-voltage breakdown between the cathode and the anode could be operated separately or simultaneously. The arc plasma expands from the cathode spot region in vacuum. In order to study the behaviors of expanding plasma plume generated in the vacuum arc plasma source, a Langmuir probe array is employed to measure the saturated ion current of the vacuum arc plasma source. The time-dependence profiles of the saturated current density of the triple vacuum arc plasma source operated separately and simultaneously are given. Furthermore, the plasma characteristic of this vacuum arc plasma source is also presented in the paper.

  9. Electrical Safety and Arc Flash Protections

    SciTech Connect (OSTI)

    R. Camp

    2008-03-04

    Over the past four years, the Electrical Safety Program at PPPL has evolved in addressing changing regulatory requirements and lessons learned from accident events, particularly in regards to arc flash hazards and implementing NFPA 70E requirements. This presentation will discuss PPPL's approaches to the areas of electrical hazards evaluation, both shock and arc flash; engineered solutions for hazards mitigation such as remote racking of medium voltage breakers, operational changes for hazards avoidance, targeted personnel training and hazard appropriate personal protective equipment. Practical solutions for nominal voltage identification and zero voltage checks for lockout/tagout will also be covered. Finally, we will review the value of a comprehensive electrical drawing program, employee attitudes expressed as a personal safety work ethic, integrated safety management, and sustained management support for continuous safety improvement.

  10. Filtered cathodic arc deposition apparatus and method

    DOE Patents [OSTI]

    Krauss, Alan R. (24461 W. Blvd. De John, Naperville, IL 60564)

    1999-01-01

    A filtered cathodic arc deposition method and apparatus for the production of highly dense, wear resistant coatings which are free from macro particles. The filtered cathodic arc deposition apparatus includes a cross shaped vacuum chamber which houses a cathode target having an evaporable surface comprised of the coating material, means for generating a stream of plasma, means for generating a transverse magnetic field, and a macro particle deflector. The transverse magnetic field bends the generated stream of plasma in the direction of a substrate. Macro particles are effectively filtered from the stream of plasma by traveling, unaffected by the transverse magnetic field, along the initial path of the plasma stream to a macro particle deflector. The macro particle deflector has a preformed surface which deflects macro particles away from the substrate.

  11. Cathodic Vacuum Arc Plasma of Thallium

    SciTech Connect (OSTI)

    Yushkov, Georgy Yu.; Anders, Andre

    2006-10-02

    Thallium arc plasma was investigated in a vacuum arc ionsource. As expected from previous consideration of cathode materials inthe Periodic Table of the Elements, thallium plasma shows lead-likebehavior. Its mean ion charge state exceeds 2.0 immediately after arctriggering, reaches the predicted 1.60 and 1.45 after about 100 microsecand 150 microsec, respectively. The most likely ion velocity is initially8000 m/s and decays to 6500 m/s and 6200 m/s after 100 microsec and 150microsec, respectively. Both ion charge states and ion velocities decayfurther towards steady state values, which are not reached within the 300microsec pulses used here. It is argued that the exceptionally high vaporpressure and charge exchange reactions are associated with theestablishment of steady state ion values.

  12. Arc Casting Intermetallic Alloy (Materials Preparation Center)

    SciTech Connect (OSTI)

    2010-01-01

    Arc casting of intermetallic (La-Ni-Sn) AB5 alloy used for metal hydride hydrogen storage. Upon solidification the Sn is partially rejected and increases in concentration in the remaining liquid. Upon completing solidification there is a great deal of internal stress in the ingot. As the ingot cools further the stress is relieved. This material was cast at the Ames Laboratorys Materials Preparation Center http://www.mpc.ameslab.gov

  13. Volumetric modulated arc radiotherapy for esophageal cancer

    SciTech Connect (OSTI)

    Vivekanandan, Nagarajan, E-mail: viveknaren@hotmail.com [Department of Medical Physics, Cancer Institute, Chennai (India); Sriram, Padmanaban; Syam Kumar, S.A.; Bhuvaneswari, Narayanan; Saranya, Kamalakannan [Department of Medical Physics, Cancer Institute, Chennai (India)

    2012-04-01

    A treatment planning study was performed to evaluate the performance of volumetric arc modulation with RapidArc (RA) against 3D conformal radiation therapy (3D-CRT) and conventional intensity-modulated radiation therapy (IMRT) techniques for esophageal cancer. Computed tomgraphy scans of 10 patients were included in the study. 3D-CRT, 4-field IMRT, and single-arc and double-arc RA plans were generated with the aim to spare organs at risk (OAR) and healthy tissue while enforcing highly conformal target coverage. The planning objective was to deliver 54 Gy to the planning target volume (PTV) in 30 fractions. Plans were evaluated based on target conformity and dose-volume histograms of organs at risk (lung, spinal cord, and heart). The monitor unit (MU) and treatment delivery time were also evaluated to measure the treatment efficiency. The IMRT plan improves target conformity and spares OAR when compared with 3D-CRT. Target conformity improved with RA plans compared with IMRT. The mean lung dose was similar in all techniques. However, RA plans showed a reduction in the volume of the lung irradiated at V{sub 20Gy} and V{sub 30Gy} dose levels (range, 4.62-17.98%) compared with IMRT plans. The mean dose and D{sub 35%} of heart for the RA plans were better than the IMRT by 0.5-5.8%. Mean V{sub 10Gy} and integral dose to healthy tissue were almost similar in all techniques. But RA plans resulted in a reduced low-level dose bath (15-20 Gy) in the range of 14-16% compared with IMRT plans. The average MU needed to deliver the prescribed dose by RA technique was reduced by 20-25% compared with IMRT technique. The preliminary study on RA for esophageal cancers showed improvements in sparing OAR and healthy tissue with reduced beam-on time, whereas only double-arc RA offered improved target coverage compared with IMRT and 3D-CRT plans.

  14. Order Reduction of the Radiative Heat Transfer Model for the Simulation of Plasma Arcs

    E-Print Network [OSTI]

    Fagiano, Lorenzo

    2015-01-01

    An approach to derive low-complexity models describing thermal radiation for the sake of simulating the behavior of electric arcs in switchgear systems is presented. The idea is to approximate the (high dimensional) full-order equations, modeling the propagation of the radiated intensity in space, with a model of much lower dimension, whose parameters are identified by means of nonlinear system identification techniques. The low-order model preserves the main structural aspects of the full-order one, and its parameters can be straightforwardly used in arc simulation tools based on computational fluid dynamics. In particular, the model parameters can be used together with the common approaches to resolve radiation in magnetohydrodynamic simulations, including the discrete-ordinate method, the P-N methods and photohydrodynamics. The proposed order reduction approach is able to systematically compute the partitioning of the electromagnetic spectrum in frequency bands, and the related absorption coefficients, tha...

  15. ArcSafe® with Pulsed Arrested Spark Discharge

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Form ArcSafe with Pulsed Arrested Spark Discharge &24; The world's only advanced electrical wiring diagnostic capable of detecting insulation defects in complex wiring systems...

  16. Arc-Fault Detector Algorithm Evaluation Method Utilizing Prerecorded...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Electrical Code Article 690.11 requires photovoltaic systems on or penetrating a building to include a DC arc-fault protection device. In order to satisfy this...

  17. PV Arc Fault Detector Challenges Due to Module Frequency Response...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    This poster does not contain any proprietary or confidential information. Introduction PV system arc faults have led to a number of rooftop fires which have caused significant...

  18. High Charge State Ions Extracted from Metal Plasmas in the Transition Regime from Vacuum Spark to High Current Vacuum Arc

    E-Print Network [OSTI]

    Anders, Georgy, Yu. Yushkov, Andre

    2008-01-01

    of expanding vacuum arc plasmas”, IEEE Trans. Plasma Sci. ,in high current vacuum arc plasma in a magnetic field,” IEEEdistributions of vacuum arc plasmas: The origin of species”,

  19. Puzzling differences in bismuth and lead plasmas: evidence for the significant role of neutrals in cathodic vacuum arcs

    E-Print Network [OSTI]

    Anders, Andre; Yushkov, Georgy Yu.

    2007-01-01

    for Pb and Bi cathodic arc plasmas revealed unexpectedCathodic vacuum arc plasmas are generally considered to beand (iv) the condensing arc plasma itself, because non-

  20. Production of neutrals and their and effects on the ion charge states in cathodic vacuum arc plasmas

    E-Print Network [OSTI]

    Anders, Andre; Oks, Efim M.; Yushkov, Georgy Yu.

    2007-01-01

    states in cathodic vacuum arc plasmas André Anders a , EfimRussia Abstract Cathodic arc plasmas are considered fullybeen known that cathodic arc plasmas go through an initial

  1. Influence of argon and oxygen on charge-state-resolved ion energy distributions of filtered aluminum arcs

    E-Print Network [OSTI]

    Rosen, Johanna; Anders, Andre; Mraz, Stanislav; Atiser, Adil; Schneider, Jochen M.

    2006-01-01

    in filtered aluminum vacuum arc plasmas were measured andI. INTRODUCTION Vacuum arc plasma is well known to be highlymeasured for vacuum arc plasmas. Aluminum plasma, for

  2. Mo-containing tetrahedral amorphous carbon deposited by dual filtered cathodic vacuum arc with selective pulsed bias voltage

    E-Print Network [OSTI]

    Pasaja, Nitisak; Sansongsiri, Sakon; Intasiri, Sawate; Vilaithong, Thiraphat; Anders, Andre

    2007-01-01

    filtered cathodic vacuum arc plasma sources with selectivedual filtered cathodic vacuum arc plasma sources operated inrepetitively pulsed vacuum arc plasma sources operating in

  3. Effect of ion mass and charge state on transport of vacuum ARC plasmas through a biased magnetic filter

    E-Print Network [OSTI]

    Byon, Eungsun; Kim, Jong-Kuk; Kwon, Sik-Chol; Anders, Andre

    2003-01-01

    G. Brown, "Transport of vacuum arc plasmas through magneticto rid cathodic arc plasma of macro- and nanoparticles: afrom cathodic arc plasmas," Surf. Coat. Technol. , vol. 133-

  4. Mo-containing tetrahedral amorphous carbon deposited by dual filtered cathodic vacuum arc with selective pulsed bias voltage

    E-Print Network [OSTI]

    Pasaja, Nitisak; Sansongsiri, Sakon; Anders, Andre; Vilaithong, Thiraphat; Intasiri, Sawate

    2006-01-01

    filtered cathodic vacuum arc plasma sources with selectiverepetitively pulsed vacuum arc plasma sources operating inthe pulse length from each arc plasma source. They concluded

  5. Electrical properties of a-C:Mo films produced by dual-cathode filtered cathodic arc plasma deposition

    E-Print Network [OSTI]

    Sansongsiri, Sakon

    2008-01-01

    cathode filtered cathodic arc plasma system. Fig. 2. Filmfiltered cathodic arc plasma deposition Sakon Sansongsiri a,filtered cathodic arc plasma deposition Sakon Sansongsiri a,

  6. Time-dependence ion charge state distributions of vacuum arcs: An interpretation involving atoms and charge exchange collisions

    E-Print Network [OSTI]

    Anders, Andre

    2004-01-01

    functions of vacuum arc plasmas," J. Appl. Phys. , vol. 93,distributions of vacuum arc plasmas: The origin of species,"energetic condensation of cathodic arc plasma. More detailed

  7. Method for controlling gas metal arc welding

    DOE Patents [OSTI]

    Smartt, Herschel B. (Idaho Falls, ID); Einerson, Carolyn J. (Idaho Falls, ID); Watkins, Arthur D. (Idaho Falls, ID)

    1989-01-01

    The heat input and mass input in a Gas Metal Arc welding process are controlled by a method that comprises calculating appropriate values for weld speed, filler wire feed rate and an expected value for the welding current by algorithmic function means, applying such values for weld speed and filler wire feed rate to the welding process, measuring the welding current, comparing the measured current to the calculated current, using said comparison to calculate corrections for the weld speed and filler wire feed rate, and applying corrections.

  8. Method for controlling gas metal arc welding

    DOE Patents [OSTI]

    Smartt, H.B.; Einerson, C.J.; Watkins, A.D.

    1987-08-10

    The heat input and mass input in a Gas Metal Arc welding process are controlled by a method that comprises calculating appropriate values for weld speed, filler wire feed rate and an expected value for the welding current by algorithmic function means, applying such values for weld speed and filler wire feed rate to the welding process, measuring the welding current, comparing the measured current to the calculated current, using said comparison to calculate corrections for the weld speed and filler wire feed rate, and applying corrections. 3 figs., 1 tab.

  9. Entropy in an Arc Plasma Source

    SciTech Connect (OSTI)

    Kaminska, A.; Dudeck, M

    2008-03-19

    The entropy properties in a D.C. argon arc plasma source are studied. The local thermodynamical entropy relations are established for a set of uniform sub-systems (Ar, Ar{sup +}, e) in order to deduce the entropy balance equation in presence of dissipative effects and in the case of a thermal non equilibrium. Phenomenological linear laws are deduced in near equilibrium situation. The flow parameters inside the plasma source are calculated by a Navier-Stokes fluid description taking into account a thermal local non equilibrium. The entropy function is calculated in the plasma source using the values of the local variables obtained from the numerical code.

  10. ScanArc ASA | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoop Inc Jump to:Newberg,EnergyEastCarbonOpen EnergyPonsa,Sasol ChevronSavannahScanArc

  11. AdaptiveARC | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoop IncIowaWisconsin: Energy Resources Jump to: navigation,Pennsylvania:AdaptiveARC

  12. VOLUME 82, NUMBER 19 P H Y S I C A L R E V I E W L E T T E R S 10 MAY 1999 Dynamic Fracture in Single Crystal Silicon

    E-Print Network [OSTI]

    Texas at Austin. University of

    VOLUME 82, NUMBER 19 P H Y S I C A L R E V I E W L E T T E R S 10 MAY 1999 Dynamic Fracture on fracture in single crystals are limited due to the difficulties in performing precisely controlled experi- ments. There is also a lack of atomic scale simulations that allow quantitative comparison with fracture

  13. Measurements of the Ion Species of Cathodic Arc Plasma in an Axial Magnetic Field

    E-Print Network [OSTI]

    Oks, Efim

    2011-01-01

    distributions of a vacuum arc plasma," Rev. Sci. Instrum. ,by filtered cathodic arc plasma," physica status solidi (a),in high current vacuum arc plasma in a magnetic field," IEEE

  14. A Summary of Recent Experimental Research on Ion Energy and Charge States of Pulsed Vacuum Arcs

    E-Print Network [OSTI]

    Oks, Efim M.

    2008-01-01

    Ion velocities in vacuum arc plasmas, J. Appl. Phys. , 2000,Anders, Cathodic Vacuum Arc Plasma of Thallium, IEEE Trans.in ca- thodic vacuum arc plasmas, J. Appl. Phys, 2007, vol.

  15. Ultrathin ta-C films on heads depositied by twist-filtered cathodic arc carbon plasmas

    E-Print Network [OSTI]

    Anders, Andre; Ryan, Francis W.

    2000-01-01

    Ion velocities in vacuum arc plasmas. submitted to J. Appl.to rid cathodic arc plasma of macro- and nanoparticles: aBrown, Transport of vacuum arc plasma through straight and

  16. Approaches to rid cathodic arc plasmas of macro- and nanoparticles: A review

    E-Print Network [OSTI]

    Anders, Andre

    2008-01-01

    Sablev, and R. I. Stupka, Plasma arc apparatus for applyingMagnetically filtered cathodic arc plasma apparatus, PatentRectangular vacuum-arc plasma source, Patent 5,480,527, Jan.

  17. Temporal Development of Ion Beam Mean Charge State in Pulsed Vacuum Arc Ion Sources

    E-Print Network [OSTI]

    Oks, Efim M.; Yushkov, Georgy Yu.; Anders, Andre

    2008-01-01

    temperature in the vacuum arc plasma and thus higher ioncharged ions in the vacuum arc plasma. The physical aspectsion charge states in vacuum arc plasma were subject of our

  18. Ion Species and Charge States of Vacuum Arc Plasma with Gas Feed and Longitudinal Magnetic Field

    E-Print Network [OSTI]

    Oks, Efim

    2010-01-01

    in cathodic vacuum arc plasmas,” J. Appl. Phys. , vol. 102,models of the cathodic arc plasma and its interaction withand Charge States of Vacuum Arc Plasma with Gas Feed and

  19. ON THE CURRENT INTENSITY LIMIT OF A VACUUM ARC ION SOURCE

    E-Print Network [OSTI]

    Brown, I.G.

    2011-01-01

    for the metal vapor vacuum arc plasma discharge employed. inin the basic vacuum arc plasma source, and we have drawnThe vacuum arc is a prolific source of metal plasma, and the

  20. Investigation of non-hydrogenated DLC:Si prepared by cathodic arc

    E-Print Network [OSTI]

    Monteiro, Othon R.; Delplancke-Ogletree, Marie-Paule

    2002-01-01

    source filtered cathodic arc plasma, and the mechanical andpulse. Typical arc current in the plasma sources were 250 Athe cathodic arc source is 1.4 (the plasma stream consists

  1. ARC Centre of Excellence for Advanced Silicon Photovoltaics

    E-Print Network [OSTI]

    New South Wales, University of

    ARC Centre of Excellence for Advanced Silicon Photovoltaics and Photonics Annual Report 2005 ARC Centre of Excellence for Advanced Silicon Photovoltaics and Photonics Annual Report 2005 #12;Centre of Excellence for Advanced Silicon Photovoltaics and Photonics is a Centre of Excellence of The Australian

  2. Mechanism of carbon nanostructure synthesis in arc plasma

    SciTech Connect (OSTI)

    Keidar, M.; Shashurin, A.; Volotskova, O.; Raitses, Y.; Beilis, I. I.

    2010-05-15

    Plasma enhanced techniques are widely used for synthesis of carbon nanostructures. The primary focus of this paper is to summarize recent experimental and theoretical advances in understanding of single-wall carbon nanotube (SWNT) synthesis mechanism in arcs, and to describe methods of controlling arc plasma parameters. Fundamental issues related to synthesis of SWNTs, which is a relationship between plasma parameters and SWNT characteristics are considered. It is shown that characteristics of synthesized SWNTs can be altered by varying plasma parameters. Effects of electrical and magnetic fields applied during SWNT synthesis in arc plasma are explored. Magnetic field has a profound effect on the diameter, chirality, and length of a SWNT synthesized in the arc plasma. An average length of SWNT increases by a factor of 2 in discharge with magnetic field and an amount of long nanotubes with the length above 5 {mu}m also increases in comparison with that observed in the discharge without a magnetic field. In addition, synthesis of a few-layer graphene in a magnetic field presence is discovered. A coupled model of plasma-electrode phenomena in atmospheric-pressure anodic arc in helium is described. Calculations indicate that substantial fraction of the current at the cathode is conducted by ions (0.7-0.9 of the total current). It is shown that nonmonotonic behavior of the arc current-voltage characteristic can be reproduced taking into account the experimentally observed dependence of the arc radius on arc current.

  3. Research Article A Customization of the Arc Marine Data

    E-Print Network [OSTI]

    Wright, Dawn Jeannine

    Research Article A Customization of the Arc Marine Data Model to Support Whale Tracking via Mate Marine Mammal Institute, Oregon State University Dawn J Wright Department of Geosciences Oregon State University Tomas Follett Marine Mammal Institute, Oregon State University Abstract The Arc Marine

  4. Applicability of moire deflection tomography for diagnosing arc plasmas

    SciTech Connect (OSTI)

    Chen Yunyun; Song Yang; He Anzhi; Li Zhenhua

    2009-01-20

    The argon arc plasma whose central temperature, 1.90x10{sup 4} K, is used as a practical example for an experiment to research the applicability of moire deflection tomography in arc plasma flow-field diagnosis. The experimental result indicates that moire deflection of the measured argon arc plasma is very small, even smaller than that of a common flame with the maximal temperature of nearly 1.80x10{sup 3} K. The refractive-index gradient in moire deflection tomography mainly contributes to the temperature gradient in essence when the probe wavelength and pressure are certain in plasma diagnosis. The applicable temperature ranges of moire deflection tomography in the argon arc plasma diagnosis are given with the probe wavelength 532 nm at 1 atm in certain measuring error requirements. In a word, the applicable temperature range of moire deflection tomography for arc plasma diagnosis is intimately related to the probe wavelength and the practical measuring requirements.

  5. Probing instabilities in arc plasma devices using binary gas mixtures

    SciTech Connect (OSTI)

    Ghorui, S.; Vysohlid, M.; Heberlein, J. V. R.; Pfender, E.

    2007-07-15

    This paper presents an experimental approach to identify the sources of instabilities in arc plasma devices. The phenomena of demixing in arcs have been utilized to explore the characteristics of different instabilities. Problems in explaining the observed behavior with our current understanding of the phenomena are discussed. Hydrogen is used as a secondary gas with argon as the primary plasma gas for this study. Results indicate that the observed behavior such as steady, takeover, and restrike modes of instabilities in arcs may essentially originate from the thin boundary layer over the anode wall primarily at the location of the anodic arc root. The bulk core flow apparently does not play any significant role in such instabilities. Arc currents rather than flow rates control the behavior of the instabilities in frequency space. Bifurcation of the system behavior and evidence for the existence of quadratic zones in flow space of binary gas mixtures separating steady and unsteady behavior are discussed.

  6. Measurement of total ion current from vacuum arc plasma sources

    SciTech Connect (OSTI)

    Oks, E.M.; Savkin, K.P.; Yushkov, G.Yu.; Nikolaev, A.G.; Anders, A.; Brown, I.G.

    2006-03-15

    The total ion current generated by a vacuum arc plasma source was measured. The discharge system investigated allowed ion collection from the arc plasma streaming through a hemispherical mesh anode with geometric transparency of 72%. A range of different cathode materials was investigated, and the arc current was varied over the range of 50-500 A. We find that the normalized ion current (I{sub ion}/I{sub arc}) depends on the cathode material, with values in the range from 5% to 19% and generally greater for elements of low cohesive energy. The application of a strong axial magnetic field in the cathode and arc region leads to increased normalized ion current, but only by virtue of enhanced ion charge states formed in a strong magnetic field.

  7. An Archean Oceanic Felsic Dyke Swarm In A Nascent Arc- The Hunter...

    Open Energy Info (EERE)

    indicate splitting of the arc. HMG and associated parts of the Abitibi greenstone belts bear a strong resemblance to modern rifted intraoceanic arcs of the western Pacific....

  8. Effect of underlayer on coalescence of silver islands grown by filtered cathodic arc deposition

    E-Print Network [OSTI]

    Byon, Eungsun; Anders, Andre

    2003-01-01

    1. A miniature pulsed cathodic arc plasma source 14) with ausing a pulsed cathodic arc plasma source with a Nb cathode.

  9. Type A Investigation of the Electrical Arc Injury at the Stanford...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    of the Electrical Arc Injury at the Stanford Linear Accelerator Complex on October 11, 2004 Type A Investigation of the Electrical Arc Injury at the Stanford Linear Accelerator...

  10. GIS Fundamentals Lesson 8: Buffering and Overlay Lesson 8: Buffering and Overlay in ArcGIS -ArcMAP

    E-Print Network [OSTI]

    Butler, Christopher J.

    GIS Fundamentals Lesson 8: Buffering and Overlay Lesson 8: Buffering and Overlay in ArcGIS - Arc. You should read chapter 9 in the GIS Fundamentals textbook. Data: All data are in \\L9 subdirectory within the bounds of an "in" polygon. 1 #12;GIS Fundamentals Lesson 8: Buffering and Overlay Surface DIST

  11. Physical characteristics of gliding arc discharge plasma generated in a laval nozzle

    SciTech Connect (OSTI)

    Lu, S. Y.; Sun, X. M.; Li, X. D.; Yan, J. H.; Du, C. M.

    2012-07-15

    The dynamic behavior of gliding arc discharge generated in a Laval nozzle has been investigated by electrical diagnostics and a high-speed camera. The results show that the voltage waveform keeps the initial shape as the gas flow rate is small, while it becomes less stable with increasing flow rate. During the first half of a cycle, the voltage rises and after that it decreases. In nitrogen and oxygen, the break down voltage for the arc is between 3.3 and 5.5 kV, while it is between 3.3-7.5 kV in air. The waveform of current I remains almost stable; and for nitrogen and oxygen, the maximum value of current I is between 0.28 and 0.46 A. With increasing flow rate, the power consumption in air first increases and then decreases; it remains in the range of 110-217 W, and gradually increases in nitrogen and oxygen. The power consumption in oxygen is lower than that in nitrogen; the input of the energy density decreases with increasing flow rate for all the three gases. The development of the arc is tracked and recorded by a high-speed camera. The cycle is stable at 10 ms for flow rates up to 1 m{sup 3} h{sup -1}. At a higher flow rate, the cycle becomes unstable.

  12. MULTIPASS MUON RLA RETURN ARCS BASED ON LINEAR COMBINED-FUNCTION MAGNETS

    SciTech Connect (OSTI)

    Vasiliy Morozov, Alex Bogacz, Yves Roblin, Kevin Beard

    2011-09-01

    Recirculating Linear Accelerators (RLA) are an efficient way of accelerating short-lived muons to the multi-GeV energies required for Neutrino Factories and TeV energies required for Muon Colliders. In this paper we present a design of a two-pass RLA return arc based on linear combined function magnets, in which both charge muons with momenta different by a factor of two are transported through the same string of magnets. The arc is composed of 60{sup o}-bending symmetric super cells allowing for a simple arc geometry closing. By adjusting the dipole and quadrupole components of the combined-function magnets, each super cell is designed to be achromatic and to have zero initial and final periodic orbit offsets for both muon momenta. Such a design provides a greater compactness than, for instance, an FFAG lattice with its regular alternating bends and is expected to possess a large dynamic aperture characteristic of linear-field lattices.

  13. Lidar arc scan uncertainty reduction through scanning geometry optimization

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wang, H.; Barthelmie, R. J.; Pryor, S. C.; Brown, G.

    2015-10-07

    Doppler lidars are frequently operated in a mode referred to as arc scans, wherein the lidar beam scans across a sector with a fixed elevation angle and the resulting measurements are used to derive an estimate of the n minute horizontal mean wind velocity (speed and direction). Previous studies have shown that the uncertainty in the measured wind speed originates from turbulent wind fluctuations and depends on the scan geometry (the arc span and the arc orientation). This paper is designed to provide guidance on optimal scan geometries for two key applications in the wind energy industry: wind turbine powermore »performance analysis and annual energy production. We present a quantitative analysis of the retrieved wind speed uncertainty derived using a theoretical model with the assumption of isotropic and frozen turbulence, and observations from three sites that are onshore with flat terrain, onshore with complex terrain and offshore, respectively. The results from both the theoretical model and observations show that the uncertainty is scaled with the turbulence intensity such that the relative standard error on the 10 min mean wind speed is about 30 % of the turbulence intensity. The uncertainty in both retrieved wind speeds and derived wind energy production estimates can be reduced by aligning lidar beams with the dominant wind direction, increasing the arc span and lowering the number of beams per arc scan. Large arc spans should be used at sites with high turbulence intensity and/or large wind direction variation when arc scans are used for wind resource assessment.« less

  14. mARC: Memory by Association and Reinforcement of Contexts

    E-Print Network [OSTI]

    Norbert Rimoux; Patrice Descourt

    2013-12-10

    This paper introduces the memory by Association and Reinforcement of Contexts (mARC). mARC is a novel data modeling technology rooted in the second quantization formulation of quantum mechanics. It is an all-purpose incremental and unsupervised data storage and retrieval system which can be applied to all types of signal or data, structured or unstructured, textual or not. mARC can be applied to a wide range of information clas-sification and retrieval problems like e-Discovery or contextual navigation. It can also for-mulated in the artificial life framework a.k.a Conway "Game Of Life" Theory. In contrast to Conway approach, the objects evolve in a massively multidimensional space. In order to start evaluating the potential of mARC we have built a mARC-based Internet search en-gine demonstrator with contextual functionality. We compare the behavior of the mARC demonstrator with Google search both in terms of performance and relevance. In the study we find that the mARC search engine demonstrator outperforms Google search by an order of magnitude in response time while providing more relevant results for some classes of queries.

  15. Modelling of arc jet plasma flow in transitional regime by Navier Stokes and state-to-state coupling

    SciTech Connect (OSTI)

    Alexandrova, T.; Izrar, B.; Lino da Silva, M.; Dudeck, M.

    2005-05-16

    The combination of 2D Navier-Stokes and state-to-state approaches has been used to describe the air plasma flow in an arc-jet. The gas dynamic parameters were calculated in Navier-Stokes approximation in a steady state description without chemical reaction and vibrational exchanges. And then, the set of equations of vibrational level densities and atomic species densities was locally solved. Experimental validations have been performed.

  16. Acoustic stabilization of electric arc instabilities in nontransferred plasma torches

    SciTech Connect (OSTI)

    Rat, V.; Coudert, J. F.

    2010-03-08

    Electric arc instabilities in dc plasma torches lead to nonhomogeneous treatments of nanosized solid particles or liquids injected within thermal plasma jets. This paper shows that an additional acoustic resonator mounted on the cathode cavity allows reaching a significant damping of these instabilities, particularly the Helmholtz mode of arc oscillations. The acoustic resonator is coupled with the Helmholtz resonator of the plasma torch limiting the amplitude of arc voltage variations. It is also highlighted that this damping is dependent on friction effects in the acoustic resonator.

  17. Numerical simulation of carbon arc discharge for nanoparticle synthesis

    SciTech Connect (OSTI)

    Kundrapu, M.; Keidar, M.

    2012-07-15

    Arc discharge with catalyst-filled carbon anode in helium background was used for the synthesis of carbon nanoparticles. In this paper, we present the results of numerical simulation of carbon arc discharges with arc current varying from 10 A to 100 A in a background gas pressure of 68 kPa. Anode sublimation rate and current voltage characteristics are compared with experiments. Distribution of temperature and species density, which is important for the estimation of the growth of nanoparticles, is obtained. The probable location of nanoparticle growth region is identified based on the temperature range for the formation of catalyst clusters.

  18. Molecular dynamics simulation comparison of atomic scale intermixing at the amorphous Al2O3/semiconductor interface for a-Al2O3/Ge, a-Al2O3/InGaAs,

    E-Print Network [OSTI]

    Kummel, Andrew C.

    /semiconductor interface for a-Al2O3/Ge, a-Al2O3/InGaAs, and a-Al2O3/InAlAs/InGaAs Evgueni A. Chagarov *, Andrew oxides Ge InGaAs InAlAs Oxide­semiconductor stack High-K oxide a b s t r a c t The structural properties of a-Al2O3/Ge, a-Al2O3/In0.5Ga0.5As and a-Al2O3/In0.5Al0.5As/InGaAs interfaces were investigated

  19. A PRELIMINARY STUDY OF DOUBLE-SIDED ARC WELDING PROCESS IN SHIP STRUCTURE MANUFACTURING

    E-Print Network [OSTI]

    Zhang, YuMing

    A PRELIMINARY STUDY OF DOUBLE-SIDED ARC WELDING PROCESS IN SHIP STRUCTURE MANUFACTURING Yu Meeting, August 21-22, 2002 #12;Objective o Determine the feasibility of double-sided arc welding process in butt welding of DH-36 plates #12;Background: Process o Double-sided arc welding (DSAW): a novel arc

  20. FusionArc optimization: A hybrid volumetric modulated arc therapy (VMAT) and intensity modulated radiation therapy (IMRT) planning strategy

    SciTech Connect (OSTI)

    Matuszak, Martha M.; McShan, Daniel L.; Ten Haken, Randall K. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48109 (United States); Steers, Jennifer M. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48109 and Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Long, Troy; Edwin Romeijn, H. [Department of Industrial and Operations Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Fraass, Benedick A. [Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, California 90048 (United States)

    2013-07-15

    Purpose: To introduce a hybrid volumetric modulated arc therapy/intensity modulated radiation therapy (VMAT/IMRT) optimization strategy called FusionArc that combines the delivery efficiency of single-arc VMAT with the potentially desirable intensity modulation possible with IMRT.Methods: A beamlet-based inverse planning system was enhanced to combine the advantages of VMAT and IMRT into one comprehensive technique. In the hybrid strategy, baseline single-arc VMAT plans are optimized and then the current cost function gradients with respect to the beamlets are used to define a metric for predicting which beam angles would benefit from further intensity modulation. Beams with the highest metric values (called the gradient factor) are converted from VMAT apertures to IMRT fluence, and the optimization proceeds with the mixed variable set until convergence or until additional beams are selected for conversion. One phantom and two clinical cases were used to validate the gradient factor and characterize the FusionArc strategy. Comparisons were made between standard IMRT, single-arc VMAT, and FusionArc plans with one to five IMRT/hybrid beams.Results: The gradient factor was found to be highly predictive of the VMAT angles that would benefit plan quality the most from beam modulation. Over the three cases studied, a FusionArc plan with three converted beams achieved superior dosimetric quality with reductions in final cost ranging from 26.4% to 48.1% compared to single-arc VMAT. Additionally, the three beam FusionArc plans required 22.4%-43.7% fewer MU/Gy than a seven beam IMRT plan. While the FusionArc plans with five converted beams offer larger reductions in final cost-32.9%-55.2% compared to single-arc VMAT-the decrease in MU/Gy compared to IMRT was noticeably smaller at 12.2%-18.5%, when compared to IMRT.Conclusions: A hybrid VMAT/IMRT strategy was implemented to find a high quality compromise between gantry-angle and intensity-based degrees of freedom. This optimization method will allow patients to be simultaneously planned for dosimetric quality and delivery efficiency without switching between delivery techniques. Example phantom and clinical cases suggest that the conversion of only three VMAT segments to modulated beams may result in a good combination of quality and efficiency.

  1. Type B Accident Investigation of the Arc Flash at Brookhaven...

    Broader source: Energy.gov (indexed) [DOE]

    event and causal factor analysis. Type B Accident Investigation of the Arc Flash at Brookhaven National Laboratory, April 14, 2006 More Documents & Publications DOE-HDBK-1092-1998...

  2. ARC-HEATED GAS FLOW EXPERIMENTS FOR HYPERSONIC PROPULSION

    E-Print Network [OSTI]

    Texas at Arlington, University of

    the Supersonic Wind Tunnel. I have enjoyed working with Rod Duke, who has been an important asset to my research to be injected into the engine combustors. To investigate this approach, the UTA Arc-Heated #12;vi Wind Tunnel

  3. Simple filtered repetitively pulsed vacuum arc plasma source

    SciTech Connect (OSTI)

    Chekh, Yu.; Zhirkov, I. S.; Delplancke-Ogletree, M. P.

    2010-02-15

    A very simple design of cathodic filtered vacuum arc plasma source is proposed. The source without filter has only four components and none of them require precise machining. The source operates in a repetitively pulsed regime, and for laboratory experiments it can be used without water cooling. Despite the simple construction, the source provides high ion current at the filter outlet reaching 2.5% of 400 A arc current, revealing stable operation in a wide pressure range from high vacuum to oxygen pressure up to more than 10{sup -2} mbar. There is no need in complicated power supply system for this plasma source, only one power supply can be used to ignite the arc, to provide the current for the arc itself, to generate the magnetic field in the filter, and provide its positive electric biasing without any additional high power resistance.

  4. Ohmic contacts for solar cells by arc plasma spraying

    DOE Patents [OSTI]

    Narasimhan, Mandayam C. (Seekonk, MA); Roessler, Barton (Barrington, RI); Loferski, Joseph J. (Providence, RI)

    1982-01-01

    The method of applying ohmic contacts to a semiconductor, such as a silicon body or wafer used in solar cells, by the use of arc plasma spraying, and solar cells resulting therefrom.

  5. Arc Reversals in Hybrid Bayesian Networks with Deterministic Variables

    E-Print Network [OSTI]

    Cinicioglu, Esma N.; Shenoy, Prakash P.

    2009-05-01

    This article discusses arc reversals in hybrid Bayesian networks with deterministic variables. Hybrid Bayesian networks contain a mix of discrete and continuous chance variables. In a Bayesian network representation, a continuous chance variable...

  6. Arc-Eager Parsing with the Tree Constraint Joakim Nivre

    E-Print Network [OSTI]

    Arc-Eager Parsing with the Tree Constraint Joakim Nivre Uppsala University Daniel Fern for greedy deterministic dependency parsers (Nivre, Hall, and Nilsson 2004; Goldberg and Nivre 2012), beam

  7. ArcGIS for Desktop Student Trial Software Instructions -Version 10.0 10.3 The ArcGIS for Desktop 1-year Student License provides a 1-year term license for ArcGIS for Desktop and Extensions

    E-Print Network [OSTI]

    O'Laughlin, Jay

    ArcGIS for Desktop Student Trial Software Instructions - Version 10.0 ­ 10.3 The ArcGIS for Desktop. Check your system requirements to make sure your computer has the hardware and software required the process of activating and downloading your ArcGIS for Desktop Student Trial software. b. Log in using your

  8. Synthesis of silicon nanotubes by DC arc plasma method

    SciTech Connect (OSTI)

    Tank, C. M.; Bhoraskar, S. V.; Mathe, V. L.

    2012-06-05

    Plasma synthesis is a novel technique of synthesis of nanomaterials as they provide high rate of production and promote metastable reactions. Very thin walled silicon nanotubes were synthesized in a DC direct arc thermal plasma reactor. The effect of parameters of synthesis i.e. arc current and presence of hydrogen on the morphology of Si nanoparticles is reported. Silicon nanotubes were characterized by Transmission Electron Microscopy (TEM), Local Energy Dispersive X-ray analysis (EDAX), and Scanning Tunneling Microscopy (STM).

  9. Role of substrate temperature at graphene synthesis in arc discharge

    E-Print Network [OSTI]

    Fang, Xiuqi; Keidar, Michael

    2015-01-01

    Substrate temperature required for synthesis of graphene in arc discharge plasma was studied. It was shown that increase of the copper substrate temperature up to melting point leads to increase in the amount of graphene production and quality of graphene sheets. Favorable range of substrate temperatures for arc-based graphene synthesis was determined in relatively narrow range of about 1340-1360K which is near the melting point of copper.

  10. Arc-Fault Detector Algorithm Evaluation Method Utilizing Prerecorded Arcing Signatures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O O D SFederal8823 Revision 02 (CRACAprilArc-Fault Detector

  11. X-Ray Photon Correlation Spectroscopy Reveals Intermittent Aging Dynamics in a Metallic Glass

    E-Print Network [OSTI]

    Zach Evenson; Beatrice Ruta; Simon Hechler; Moritz Stolpe; Eloi Pineda; Isabella Gallino; Ralf Busch

    2015-09-02

    We use coherent X-rays to probe the aging dynamics of a metallic glass directly on the atomic level. Contrary to the common assumption of a steady slowing down of the dynamics usually observed in macroscopic studies, we show that the structural relaxation processes underlying aging in this metallic glass are intermittent and highly heterogeneous at the atomic scale. Moreover, physical aging is triggered by cooperative atomic rearrangements, driven by the relaxation of internal stresses. The rich diversity of this behavior reflects a complex energy landscape, giving rise to a unique type of glassy-state dynamics.

  12. Arc-parallel flow within the mantle wedge: Evidence from the accreted Talkeetna arc, south central Alaska

    E-Print Network [OSTI]

    Alaska Luc Mehl and Bradley R. Hacker Department of Geological Sciences, University of California, Santa. Hacker, G. Hirth, and P. B. Kelemen, Arc-parallel flow within the mantle wedge: Evidence from

  13. JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 88, NO. B9, PAGES 7429-7448, SEPTEMBER 10,1983 --BACK ARC THRUSTING IN THE EASTERN SUNDA ARC, INDONESIA

    E-Print Network [OSTI]

    McCaffrey, Robert

    THRUSTING IN THE EASTERN SUNDA ARC, INDONESIA: A CONSEQUENCE OF ARC-CONTINENT COLLISION Eli A. Silver Center, Jalan Diponegoro 57, Bandung, Indonesia Abstract. The structure of the eastern Sunda convergence

  14. ARCS Additional FirstYear PhD Student Award The Atlanta chapter of ARCS has just informed me that they will honor us with another graduate student

    E-Print Network [OSTI]

    Arnold, Jonathan

    ARCS Additional FirstYear PhD Student Award The Atlanta chapter of ARCS has just informed me meets their definition listed above. Sincerely, Harry A. Dailey, Ph.D. Professor and Director

  15. Use of a Magnetized Cascade Arc SourceUse of a Magnetized Cascade Arc Source in TCSU to Enable RMF Formation ofin TCSU to Enable RMF Formation of

    E-Print Network [OSTI]

    Washington at Seattle, University of

    erosion rate but must still be machinable. All arc discharges to date with this plasma gun have been madeUse of a Magnetized Cascade Arc SourceUse of a Magnetized Cascade Arc Source in TCSU to Enable RMF.Y. Guo, K.E. Miller Redmond Plasma Physics Laboratory, University of Washington Abstract TCSU can produce

  16. Graphite electrode arc melter demonstration Phase 2 test results

    SciTech Connect (OSTI)

    Soelberg, N.R.; Chambers, A.G.; Anderson, G.L.; O`Connor, W.K.; Oden, L.L.; Turner, P.C.

    1996-06-01

    Several U.S. Department of Energy organizations and the U.S. Bureau of Mines have been collaboratively conducting mixed waste treatment process demonstration testing on the near full-scale graphite electrode submerged arc melter system at the Bureau`s Albany (Oregon) Research Center. An initial test series successfully demonstrated arc melter capability for treating surrogate incinerator ash of buried mixed wastes with soil. The conceptual treatment process for that test series assumed that buried waste would be retrieved and incinerated, and that the incinerator ash would be vitrified in an arc melter. This report presents results from a recently completed second series of tests, undertaken to determine the ability of the arc melter system to stably process a wide range of {open_quotes}as-received{close_quotes} heterogeneous solid mixed wastes containing high levels of organics, representative of the wastes buried and stored at the Idaho National Engineering Laboratory (INEL). The Phase 2 demonstration test results indicate that an arc melter system is capable of directly processing these wastes and could enable elimination of an up-front incineration step in the conceptual treatment process.

  17. Parallel vacuum arc discharge with microhollow array dielectric and anode

    SciTech Connect (OSTI)

    Feng, Jinghua; Zhou, Lin; Fu, Yuecheng; Zhang, Jianhua; Xu, Rongkun; Chen, Faxin; Li, Linbo; Meng, Shijian

    2014-07-15

    An electrode configuration with microhollow array dielectric and anode was developed to obtain parallel vacuum arc discharge. Compared with the conventional electrodes, more than 10 parallel microhollow discharges were ignited for the new configuration, which increased the discharge area significantly and made the cathode eroded more uniformly. The vacuum discharge channel number could be increased effectively by decreasing the distances between holes or increasing the arc current. Experimental results revealed that plasmas ejected from the adjacent hollow and the relatively high arc voltage were two key factors leading to the parallel discharge. The characteristics of plasmas in the microhollow were investigated as well. The spectral line intensity and electron density of plasmas in microhollow increased obviously with the decease of the microhollow diameter.

  18. Muon Acceleration with RLA and Non-scaling FFAG Arcs

    SciTech Connect (OSTI)

    Vasiliy Morozov,Alex Bogacz,Dejan Trbojevic

    2010-05-01

    Recirculating Linear Accelerators (RLA) are the most likely means to achieve the rapid acceleration of shortlived muons to multi-GeV energies required for Neutrino Factories and TeV energies required for Muon Colliders. In this paper, we present a novel return-arc optics design based on a Non Scaling Fixed Field Alternating Gradient (NS-FFAG) lattice that allows 5 and 9 GeV/c muons of both charges to be transported in the same string of magnets. The return arcs are made up of super cells with each super cell consisting of three triplets. By employing combined function magnets with dipole, quadrupole, sextupole and octupole magnetic field components, each super cell is designed to be achromatic and to have zero initial and final periodic orbit offsets for both 5 and 9 GeV/c muon momenta. This solution would reduce the number of arcs by a factor of 2, simplifying the overall design.

  19. Muon acceleration with RLA and non-scaling FFAG ARCS

    SciTech Connect (OSTI)

    Morozov, V.S.; Trbojevic, D.; Bogacz, A.

    2010-05-23

    Recirculating Linear Accelerators (RLA) are the most likely means to achieve the rapid acceleration of short-lived muons to multi-GeV energies required for Neutrino Factories and TeV energies required for Muon Colliders. In this paper, we present a novel return-arc optics design based on a Non Scaling Fixed Field Alternating Gradient (NS-FFAG) lattice that allows 5 and 9 GeV/c muons of both charges to be transported in the same string of magnets. The return arcs are made up of super cells with each super cell consisting of three triplets. By employing combined function magnets with dipole, quadrupole, sextupole and octupole magnetic field components, each super cell is designed to be achromatic and to have zero initial and final periodic orbit offsets for both 5 and 9 GeV/c muon momenta. This solution would reduce the number of arcs by a factor of 2, simplifying the overall design.

  20. High-bandwidth continuous-flow arc furnace

    DOE Patents [OSTI]

    Hardt, D.E.; Lee, S.G.

    1996-08-06

    A high-bandwidth continuous-flow arc furnace for stream welding applications includes a metal mass contained in a crucible having an orifice. A power source charges an electrode for generating an arc between the electrode and the mass. The arc heats the metal mass to a molten state. A pressurized gas source propels the molten metal mass through the crucible orifice in a continuous stream. As the metal is ejected, a metal feeder replenishes the molten metal bath. A control system regulates the electrode current, shielding gas pressure, and metal source to provide a continuous flow of molten metal at the crucible orifice. Independent control over the electrode current and shield gas pressure decouples the metal flow temperature and the molten metal flow rate, improving control over resultant weld characteristics. 4 figs.

  1. High-bandwidth continuous-flow arc furnace

    DOE Patents [OSTI]

    Hardt, David E. (Concord, MA); Lee, Steven G. (Ann Arbor, MI)

    1996-01-01

    A high-bandwidth continuous-flow arc furnace for stream welding applications includes a metal mass contained in a crucible having an orifice. A power source charges an electrode for generating an arc between the electrode and the mass. The arc heats the metal mass to a molten state. A pressurized gas source propels the molten metal mass through the crucible orifice in a continuous stream. As the metal is ejected, a metal feeder replenishes the molten metal bath. A control system regulates the electrode current, shielding gas pressure, and metal source to provide a continuous flow of molten metal at the crucible orifice. Independent control over the electrode current and shield gas pressure decouples the metal flow temperature and the molten metal flow rate, improving control over resultant weld characteristics.

  2. Achieving high mobility ZnO:Al at very high growth rates by dc filtered cathodic arc deposition

    E-Print Network [OSTI]

    Mendelsberg, Rueben

    2013-01-01

    scale heating in cathodic arc plasma deposition. Appl. Phys.modest 25-70 A dc. The arc plasma was ?ltered using aenergy of the cathodic arc plasma is utilized for ?lm growth

  3. Improved structural and electrical properties of thin ZnO:Al films by dc filtered cathodic arc deposition

    E-Print Network [OSTI]

    Zhu, Yuankun

    2013-01-01

    scale heating in cathodic arc plasma deposition. Appl. Phys.using filtered cathodic arc plasmas. Vacuum 67 673 (2002).to rid cathodic arc plasma of macro- and nanoparticles: a

  4. Multi-cathode metal vapor arc ion source

    DOE Patents [OSTI]

    Brown, Ian G. (1088 Woodside Rd., Berkeley, CA 94708); MacGill, Robert A. (645 Kern St., Richmond, CA 94805)

    1988-01-01

    An ion generating apparatus utilizing a vacuum chamber, a cathode and an anode in the chamber. A source of electrical power produces an arc or discharge between the cathode and anode. The arc is sufficient to vaporize a portion of the cathode to form a plasma. The plasma is directed to an extractor which separates the electrons from the plasma, and accelerates the ions to produce an ion beam. One embodiment of the appaatus utilizes a multi-cathode arrangement for interaction with the anode.

  5. Graphite electrode DC arc furnace. Innovative technology summary report

    SciTech Connect (OSTI)

    1999-05-01

    The Graphite Electrode DC Arc Furnace (DC Arc) is a high-temperature thermal process, which has been adapted from a commercial technology, for the treatment of mixed waste. A DC Arc Furnace heats waste to a temperature such that the waste is converted into a molten form that cools into a stable glassy and/or crystalline waste form. Hazardous organics are destroyed through combustion or pyrolysis during the process and the majority of the hazardous metals and radioactive components are incorporated in the molten phase. The DC Arc Furnace chamber temperature is approximately 593--704 C and melt temperatures are as high as 1,500 C. The DC Arc system has an air pollution control system (APCS) to remove particulate and volatiles from the offgas. The advantage of the DC Arc is that it is a single, high-temperature thermal process that minimizes the need for multiple treatment systems and for extensive sorting/segregating of large volumes of waste. The DC Arc has the potential to treat a wide range of wastes, minimize the need for sorting, reduce the final waste volumes, produce a leach resistant waste form, and destroy organic contaminants. Although the DC arc plasma furnace exhibits great promise for treating the types of mixed waste that are commonly present at many DOE sites, several data and technology deficiencies were identified by the Mixed Waste Focus Area (MWFA) regarding this thermal waste processing technique. The technology deficiencies that have been addressed by the current studies include: establishing the partitioning behavior of radionuclides, surrogates, and hazardous metals among the product streams (metal, slag, and offgas) as a function of operating parameters, including melt temperature, plenum atmosphere, organic loading, chloride concentration, and particle size; demonstrating the efficacy of waste product removal systems for slag and metal phases; determining component durability through test runs of extended duration, evaluating the effect of feed composition variations on process operating conditions and slag product performance; and collecting mass balance and operating data to support equipment and instrument design.

  6. Thermocapillary and arc phenomena in stainless steel welds

    SciTech Connect (OSTI)

    Pierce, S.W.

    1993-10-01

    Goal was to study effect of power level and distribution on thermocapiilary-induced weld shape and of arc factors on weld shape. Thermocapillarity was apparent in both conduction mode EB welds and GTA welds, particularly in the former. A non-Gaussian arc distribution is suggested for accounting for the differences between the twoss processes. At higher current levels (200--300 A), plasma shear force also contributes to weld shape development. Evidence suggests that thermocapillary flow reversal is not a factor in normal GTA welds; EDB flow reversal occurs only at high power density levels where the keyhole mode is present.

  7. Emission spectra analysis of arc plasma for synthesis of carbon nanostructures in various magnetic conditions

    SciTech Connect (OSTI)

    Li Jian; Kundrapu, Madhusudhan; Shashurin, Alexey; Keidar, Michael

    2012-07-15

    Arc discharge supported by the erosion of anode materials is one of the most practical and efficient methods to synthesize various high-quality carbon nanostructures. By introducing a non-uniform magnetic field in arc plasmas, high-purity single-walled carbon nanotubes (SWCNT) and large-scale graphene flakes can be obtained in a single step. In this paper, ultraviolet-visible emission spectra of arc in different spots under various magnetic conditions are analyzed to provide an in situ investigation for transformation processes of evaporated species and growth of carbon nanostructures in arc. Based on the arc spectra of carbon diatomic Swan bands, vibrational temperature in arc is determined. The vibrational temperature in arc center was measured around 6950 K, which is in good agreement with our simulation results. Experimental and simulation results suggest that SWCNT are formed in the arc periphery region. Transmission electronic microscope and Raman spectroscope are also employed to characterize the properties of carbon nanostructures.

  8. Optical emission spectroscopy of metal vapor dominated laser-arc hybrid welding plasma

    SciTech Connect (OSTI)

    Ribic, B.; DebRoy, T.; Burgardt, P.

    2011-04-15

    During laser-arc hybrid welding, plasma properties affect the welding process and the weld quality. However, hybrid welding plasmas have not been systematically studied. Here we examine electron temperatures, species densities, and electrical conductivity for laser, arc, and laser-arc hybrid welding using optical emission spectroscopy. The effects of arc currents and heat source separation distances were examined because these parameters significantly affect weld quality. Time-average plasma electron temperatures, electron and ion densities, electrical conductivity, and arc stability decrease with increasing heat source separation distance during hybrid welding. Heat source separation distance affects these properties more significantly than the arc current within the range of currents considered. Improved arc stability and higher electrical conductivity of the hybrid welding plasma result from increased heat flux, electron temperatures, electron density, and metal vapor concentrations relative to arc or laser welding.

  9. Charge-State-Resolved Ion Energy Distribution Functions of Cathodic Vacuum Arcs: A Study Involving the Plasma Potential and Biased Plasmas

    E-Print Network [OSTI]

    Anders, Andre; Oks, Efim

    2006-01-01

    velocity in vacuum arc plasmas by arc current perturbationwith a pulsed cathodic arc plasma source of the “minigun”produced by a cathodic arc plasma source of the “minigun”

  10. THE CONTROL OF A HIGH-POWER NEUTRAL BEAM GENERATOR BY MEANS OF ARC-CURRENT REGULATION

    E-Print Network [OSTI]

    Lietzke, A.F.

    2010-01-01

    A HIGH-POWER NEUTRAL BEAM GENERATOR BY MEANS OF ARC-CURRENTA HIGH-POWER NEUTRAL BEAM GENERATOR BY MEANS OF ARC-CURRENT

  11. A comparison of the marginal adaptation of cathode-arc vapor-deposited titanium and cast base metal copings.

    E-Print Network [OSTI]

    Wu, Jean C; Lai, Li-Chung; Sheets, Cherilyn G; Earthman, James; Newcomb, Robert

    2011-01-01

    of Prosthetic Dentistry plasma arc on the cathode surface.arc deposition consists of a titanium cathode material and metal plasma

  12. Seminar (Winter '10) 16th ARC Conference Events Archive ARC Collaborative Research Seminar Series

    E-Print Network [OSTI]

    Papalambros, Panos

    Debevec, PhD We will present our work in building virtual humans at the ICT. We will cover new technology with preliminary validation and validation plans. Dynamic tire model for real-time human-in-the-loop driving we are developing to create life-like animations that can be controlled dynamically by an artificial

  13. Physics 619: Fields II Fall 2014 Room: ARC-212

    E-Print Network [OSTI]

    Gustafsson, Torgny

    Physics 619: Fields II Fall 2014 Room: ARC-212 Time: Monday, Thursday 10:20-11:40 AM Instructor: Sergei Lukyanov office: Serin E364 tel: (848) 445-9060 (office) e-mail: sergei@physics.rutgers.edu (the to the published version) can be found at http://web.physics.ucsb.edu/ mark/ms-qft-DRAFT.pdf Homework

  14. Connecting ARC/INFO \\Lambda and SNACTor Project Report y

    E-Print Network [OSTI]

    Krovi, Venkat

    This report describes an interface between ARC/INFO, a geographic information management system, and SNACTor of how an interaction with a geographic 2 #12; information management system could be done in a small and Hsueh­cheng Chou x National Center for Geographic Information and Analysis June 8, 1992 Abstract

  15. Self-organisation Processes In The Carbon ARC For Nanosynthis

    SciTech Connect (OSTI)

    Ng, J.; Raitses, Yefgeny

    2014-02-02

    The atmospheric pressure carbon arc in inert gases such as helium is an important method for the production of nanomaterials. It has recently been shown that the formation of the carbon deposit on the cathode from gaseous carbon plays a crucial role in the operation of the arc, reaching the high temperatures necessary for thermionic emission to take place even with low melting point cathodes. Based on observed ablation and deposition rates, we explore the implications of deposit formation on the energy balance at the cathode surface, and show how the operation of the arc is self-organised process. Our results suggest that the can arc operate in two di erent regimes, one of which has an important contribution from latent heat to the cathode energy balance. This regime is characterised by the enhanced ablation rate, which may be favourable for high yield synthesis of nanomaterials. The second regime has a small and approximately constant ablation rate with a negligible contribution from latent heat.

  16. Self-organisation Processes In The Carbon ARC For Nanosynthis

    SciTech Connect (OSTI)

    Ng, Jonathan; Raitses, Yevgeny

    2014-02-26

    The atmospheric pressure carbon arc in inert gases such as helium is an important method for the production of nanomaterials. It has recently been shown that the formation of the carbon deposit on the cathode from gaseous carbon plays a crucial role in the operation of the arc, reaching the high temperatures necessary for thermionic emission to take place even with low melting point cathodes. Based on observed ablation and deposition rates, we explore the implications of deposit formation on the energy balance at the cathode surface, and show how the operation of the arc is self-organised process. Our results suggest that the can arc operate in two di erent regimes, one of which has an important contribution from latent heat to the cathode energy balance. This regime is characterised by the enhanced ablation rate, which may be favourable for high yield synthesis of nanomaterials. The second regime has a small and approximately constant ablation rate with a negligible contribution from latent heat.

  17. Supersonic Argon Flow In An Arc Plasma Source

    SciTech Connect (OSTI)

    Izrar, B.; Dudeck, M.; Andre, P.; Elchinger, M. F.; Aubreton, J.

    2006-01-15

    The plasma properties inside a D.C. arc-jet operating with argon is analysed by means of a continuum description taking into account non equilibrium ionization processes and dissipative effects. The relaxation of the different physical processes inside the nozzle and the evolution of the Mach number are aanalysed.

  18. H2O subduction beyond arcs Bradley R. Hacker

    E-Print Network [OSTI]

    Hacker, Bradley R.

    H2O subduction beyond arcs Bradley R. Hacker Department of Earth Science, University of California, Santa Barbara, California 93109-9630, USA (hacker@geol.ucsb.edu) [1] The amount of H2O subducted). Received 31 May 2007; Revised 26 October 2007; Accepted 7 December 2007; Published 5 March 2008. Hacker, B

  19. Pulse thermal processing of functional materials using directed plasma arc

    DOE Patents [OSTI]

    Ott, Ronald D. (Knoxville, TN); Blue, Craig A. (Knoxville, TN); Dudney, Nancy J. (Knoxville, TN); Harper, David C. (Kingston, TN)

    2007-05-22

    A method of thermally processing a material includes exposing the material to at least one pulse of infrared light emitted from a directed plasma arc to thermally process the material, the pulse having a duration of no more than 10 s.

  20. The Arc type Dependence Representation in Polaris Naraig Manjikian

    E-Print Network [OSTI]

    Padua, David

    The Arc type Dependence Representation in Polaris Naraig Manjikian Department of Electrical and Computer Engineering University of Toronto Toronto, Ontario, Canada M5S 1A4 May 20, 1995 1 Introduction in a dependence pair, i.e., there is no redundant information. The implication of this is that both a source

  1. End of Year reporting & Carry forward process for ARC & NHMRC

    E-Print Network [OSTI]

    Blennerhassett, Peter

    End of Year reporting & Carry forward process for ARC & NHMRC PREPARATION · September - GMO sends reminder email to CIs to review research account expenditure · October - GMO sends advice to all CIs Financial Statement amounts and GMO classifies accounts according to reporting required; % of carry forward

  2. Anode Sheath Switching in a Carbon Nanotube Arc Plasma

    SciTech Connect (OSTI)

    Abe Fetterman, Yevgeny Raitses, and Michael Keidar

    2008-04-08

    The anode ablation rate is investigated as a function of anode diameter for a carbon nanotube arc plasma. It is found that anomalously high ablation occurs for small anode diameters. This result is explained by the formation of a positive anode sheath. The increased ablation rate due to this positive anode sheath could imply greater production rate for carbon nanotubes.

  3. Study of the spray to globular transition in gas metal arc welding: a spectroscopic investigation

    E-Print Network [OSTI]

    Study of the spray to globular transition in gas metal arc welding: a spectroscopic investigation of the spray to globular transition in gas metal arc welding: a spectroscopic investigation F Valensi1.iop.org/JPhysD/46/224005 Abstract The gas metal arc welding (GMAW) process is strongly influenced by the composition

  4. Proposal of an Arc Detection Technique Based on RF Measurements for the ITER ICRF Antenna

    SciTech Connect (OSTI)

    Huygen, S.; Dumortier, P.; Durodie, F.; Messiaen, A.; Vervier, M.; Vrancken, M.

    2011-12-23

    RF arc detection is a key operational and safety issue for the ICRF system on ITER. Indeed the high voltages inside the antenna put it at risk of arcing, which could cause substantial damage. This paper describes the various possibilities explored by circuit simulation and the strategy now considered to protect the ITER ICRF antenna from RF arcs.

  5. Comparison of Different Arc Detection Methods during Plasma Operations with ICRF Heating on ASDEX Upgrade

    SciTech Connect (OSTI)

    D'Inca, R.; Assas, S.; Bobkov, V.; Braun, F.; Eckert, B.; Noterdaeme, J.-M.

    2007-09-28

    The Sub-Harmonic Arc Detection (SHAD) system used on ASDEX-Upgrade has been designed with the double objective to detect arcs on the ICRF system and to discriminate them from plasma transients like ELMs. This preliminary study focuses on the achievement of these requirements by analyzing and comparing the behavior of the SHAD with existing arc detectors in operation on AUG.

  6. Sediment Budget Analysis System (SBAS) for ArcGIS 10 -User's Guide Page 1 of 50

    E-Print Network [OSTI]

    US Army Corps of Engineers

    Sediment Budget Analysis System (SBAS) for ArcGIS 10 - User's Guide Page 1 of 50 CESAM-OPJ-GIS Document current as of June 27, 2012 10:09 AM Sediment Budget Analysis System (SBAS) for ArcGIS 10 User's Guide D R AFT #12;Sediment Budget Analysis System (SBAS) for ArcGIS 10 - User's Guide Page 2 of 50 CESAM

  7. Electrical Simulations of Series and Parallel PV Arc-Faults Jack Flicker and Jay Johnson

    E-Print Network [OSTI]

    Electrical Simulations of Series and Parallel PV Arc-Faults Jack Flicker and Jay Johnson Sandia residential and commercial rooftop fires. The National Electrical Code® (NEC) added section 690.11 to mitigate the electrical behavior of the PV system during series and parallel arc-faults to (a) understand the arcing power

  8. The impulse response of a high-speed jet forced with localized arc filament plasma actuators

    E-Print Network [OSTI]

    Colonius, Tim

    The impulse response of a high-speed jet forced with localized arc filament plasma actuators arc filament plasma actuators Aniruddha Sinha,1 Hind Alkandry,2 Martin Kearney-Fischer,3 Mo Samimy,2,a to impulsive forcing with arc-filament-plasma actuators. The impulse response is obtained with forcing Strouhal

  9. Parametric Study of PV Arc-Fault Generation Methods and Analysis of Conducted DC Spectrum

    E-Print Network [OSTI]

    Parametric Study of PV Arc-Fault Generation Methods and Analysis of Conducted DC Spectrum Jay photovoltaic (PV) direct current (DC) arc- fault detectors use the frequency content of the PV system to detect by different PV arcs in the field. In this investigation, we (a) discuss the differences in establishing

  10. Glass Inclusions in Mariana Arc Phenocrysts: A New Perspective on Magmatic Evolution in a Typical Intra-oceanic Arc1

    E-Print Network [OSTI]

    Stern, Robert J.

    Glass Inclusions in Mariana Arc Phenocrysts: A New Perspective on Magmatic Evolution in a Typical at Dallas, Box 830688, Richardson, TX 75083-0688, USA A B S T R A C T Major element compositions of glass of these lavas reflects accumulation of plagioclase. Glass inclusions also show the common occurrence of felsic

  11. Arc Basalt Simulator version 2, a simulation for slab dehydration and fluid-fluxed mantle melting for arc

    E-Print Network [OSTI]

    Stern, Robert J.

    @jamstec.go.jp) Bradley R. Hacker Department of Earth Science, University of California, Santa Barbara, California 93106-9630, USA (hacker@geol.ucsb.edu) Peter E. van Keken Department of Geological Sciences, University. Hacker, P. E. van Keken, H. Kawabata, T. Yoshida, and R. J. Stern (2009), Arc Basalt Simulator version 2

  12. In situ observations of the "preexisting auroral arc" by THEMIS all sky imagers and the FAST spacecraft

    E-Print Network [OSTI]

    California at Berkeley, University of

    ) The preexisting arc is located 1 $2 poleward of the equatorward edge of the 1 keV electron plasma sheetIn situ observations of the "preexisting auroral arc" by THEMIS all sky imagers and the FAST involve brightening followed by poleward expansion of a discrete auroral arc. The arc that brightens

  13. Multistage CSR microbunching gain development in transport or recirculation arcs

    E-Print Network [OSTI]

    Tsai, Cheng-Ying; Li, Rui; Tennant, Chris

    2015-01-01

    Coherent synchrotron radiation (CSR) induced microbunching instability has been one of the most challenging issues in the design of modern accelerators. A linear Vlasov solver has been developed [1] and applied to investigate the physical processes of microbunching gain amplification for several example lattices [2]. In this paper, by further extending the concept of stage gain as proposed by Huang and Kim [3], we develop a method to characterize the microbunching development in terms of stage orders that allow the quantitative comparison of optics impacts on microbunching gain for different lattices. We find that the microbunching instability in our demonstrated arcs has a distinguishing feature of multistage amplification (e.g, up to 6th stage amplification for our example transport arcs, in contrast to two-stage amplification for a typical 4-dipole bunch compressor chicane). We also try to connect lattice optics pattern with the obtained stage gain functions by a physical interpretation. This Vlasov analys...

  14. Comparative Analysis of Carbon Plasma in Arc and RF Reactors

    SciTech Connect (OSTI)

    Todorovic-Markovic, B.; Markovic, Z.; Mohai, I.; Szepvolgyi, J.

    2004-12-01

    Results on studies of molecular spectra emitted in the initial stages of fullerene formation during the processing of graphite powder in induction RF reactor and evaporation of graphite electrodes in arc reactor are presented in this paper. It was found that C2 radicals were dominant molecular species in both plasmas. C2 radicals have an important role in the process of fullerene synthesis. The rotational-vibrational temperatures of C2 and CN species were calculated by fitting the experimental spectra to the simulated ones. The results of optical emission study of C2 radicals generated in carbon arc plasma have shown that rotational temperature of C2 species depends on carbon concentration and current intensity significantly. The optical emission study of induction RF plasma and SEM analysis of graphite powder before and after plasma treatment have shown that evaporation of the processed graphite powder depends on feed rate and composition of gas phase significantly. Based on the obtained results, it was concluded that in the plasma region CN radicals could be formed by the reaction of C2 species with atomic nitrogen at smaller loads. At larger feed rate of graphite powder, CN species were produced by surface reaction of the hot carbon particles with nitrogen atoms. The presence of nitrogen in induction RF plasma reduces the fullerene yield significantly. The fullerene yield obtained in two different reactors was: 13% in arc reactor and 4.1% in induction RF reactor. However, the fullerene production rate was higher in induction RF reactor-6.4 g/h versus 1.7 g/h in arc reactor.

  15. An interchangeable-cathode vacuum arc plasma source

    SciTech Connect (OSTI)

    Olson, David K.; Peterson, Bryan G.; Hart, Grant W.

    2010-01-15

    A simplified vacuum arc design [based on metal vapor vacuum arc (MeVVA) concepts] is employed as a plasma source for a study of a {sup 7}Be non-neutral plasma. The design includes a mechanism for interchanging the cathode source. Testing of the plasma source showed that it is capable of producing on the order of 10{sup 12} charges at confinable energies using a boron-carbide disk as the cathode target. The design is simplified from typical designs for lower energy and lower density applications by using only the trigger spark rather than the full vacuum arc in high current ion beam designs. The interchangeability of the cathode design gives the source the ability to replace only the source sample, simplifying use of radioactive materials in the plasma source. The sample can also be replaced with a completely different conductive material. The design can be easily modified for use in other plasma confinement or full MeVVA applications.

  16. RF Arc Detection in ICRH RDL Antennas by Phase Measurement

    SciTech Connect (OSTI)

    El Khaldi, M.; Vulliez, K.; Magne, R.; Bosia, G.

    2009-11-26

    A voltage breakdown in an Ion Cyclotron Resonance Heating (ICRH) system is usually detected as an abrupt change in the module of the reflection coefficient |{gamma}in| at the power source output. The same effect can be due to a large load variation. This study is carried out by constructing a electrical model for a Tore Supra ITER-like antenna (TS ILA), and to analyse how a voltage breakdown, localized in any part of the system, modifies several electrical parameters of the circuit (with respect to perfect match conditions), as detected at the location of the monitoring points. The phase difference between the reflections coefficients measured at the output of tuning network when an arc strikes in one of two Resonant double loop (RDL) sections of the ICRH TS ILA appears to be the most promising parameter to detect the arc and identify its position. It is also significantly insensitive to a load variation so an arc and edge localized modes (ELMs) can be distinguished.

  17. Arc Plasma Synthesis of Nanostructured Materials: Techniques and Innovations

    SciTech Connect (OSTI)

    Das, A. K.; Bhoraskar, S. V.; Kakati, M.; Karmakar, Soumen

    2008-10-23

    Arc plasma aided synthesis of nanostructured materials has the potential of producing complex nano phase structures in bulk quantities. Successful implementation of this potential capability to industrial scale nano generation needs establishment of a plasma parameter control regime in terms of plasma gas, flow pattern, pressure, local temperature and the plasma fields to obtain the desired nano phase structures. However, there is a need to design innovative in situ experiments for generation of an extensive database and subsequently to correlate plasma parameters to the size, shape and phase of the generated nanostructures. The present paper reviews the various approaches utilized in the field of arc plasma nanosynthesis in general and in the authors' laboratories in particular. Simple plasma diagnostics and monitoring schemes have been used in conjunction with nano materials characterization tools to explore the possibility of controlling the size, shape, yield and phase composition of the arc generated nanostructures through plasma control. Case studies related to synthesis of AlN, Al2O3, TiO2, ZrO2, ZnO), magnetic (e.g. {gamma}-Fe2O3, Fe3O4) and single elemental materials (e.g. carbon nanotubes) are presented.

  18. Vacuum Arc Ion Sources: Recent Developments and Applications

    SciTech Connect (OSTI)

    Brown, Ian; Oks, Efim

    2005-05-01

    The vacuum arc ion source has evolved over the past twenty years into a standard laboratory tool for the production of high current beams of metal ions, and is now used in a number of different embodiments at many laboratories around the world. The primary application of this kind of source has evolved to be ion implantation for material surface modification. Another important use is for injection of high current beams of heavy metal ions into the front ends of particle accelerators, and much excellent work has been carried out in recent years in optimizing the source for reliable accelerator application. The source also provides a valuable tool for the investigation of the fundamental plasma physics of vacuum arc plasma discharges. As the use of the source has grown and diversified, at the same time the ion source performance and operational characteristics have been improved in a variety of different ways also. Here we review the growth and status of vacuum arc ion sources around the world, and summarize some of the applications for which the sources have been used.

  19. Experiments with background gas in a vacuum arc centrifuge

    SciTech Connect (OSTI)

    Dallaqua, R.S.; Simpson, S.W.; Del Bosco, E.

    1996-04-01

    Since promising isotope separation results were first reported by Krishnan et al. in 1981, a range of vacuum arc centrifuge experiments have been conducted in laboratories around the world. The PCEN (Plasma CENtrifuge) vacuum arc centrifuge at the Brazilian National Institute for Space Research has been used for isotope separation studies with cathode materials of carbon and magnesium and also to investigate the performance in terms of the rotational velocity attained for different cathode materials. Here, a vacuum arc centrifuge has been operated with an initial filling gas of either argon or hydrogen for pressures ranging from 10{sup {minus}3} to 10{sup {minus}1} Pa. The angular velocity {omega} of the plasma has been determined by cross-correlating the signals from potential probes, and the electron temperature T has been deduced from Langmuir probe data. At high gas pressures and early times during the 14 ms plasma lifetime, high-frequency nonuniformities frequently observed in the vacuum discharge disappear, suggesting that the associated instability is suppressed. Under the same conditions, nonuniformities rotating with much lower angular velocities are observed in the plasma. Temperatures are reduced in the presence of the background gas, and the theoretical figure of merit for separation proportional to {omega}{sup 2}/T is increased compared to its value in the vacuum discharge for both argon and hydrogen gas fillings.

  20. QUANTIFYING PHOTOVOLTAIC FIRE DANGER REDUCTION WITH ARC-FAULT CIRCUIT INTERRUPTERS

    E-Print Network [OSTI]

    QUANTIFYING PHOTOVOLTAIC FIRE DANGER REDUCTION WITH ARC-FAULT CIRCUIT INTERRUPTERS Kenneth M, shock hazards, and cause system downtime in photovoltaic (PV) systems. The 2011 National Electrical Code

  1. Sandia Energy - PV Arc-Fault and Ground Fault Detection and Mitigation...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Program Home Stationary Power Energy Conversion Efficiency Solar Energy Photovoltaics PV Systems Reliability PV Arc-Fault and Ground Fault Detection and Mitigation Program PV...

  2. Formation of metal oxides by cathodic arc deposition

    SciTech Connect (OSTI)

    Anders, S.; Anders, A.; Rubin, M.; Wang, Z.; Raoux, S.; Kong, F.; Brown, I.G.

    1995-03-01

    Metal oxide thin films are of interest for a number of applications. Cathodic arc deposition, an established, industrially applied technique for formation of nitrides (e.g. TiN), can also be used for metal oxide thin film formation. A cathodic arc plasma source with desired cathode material is operated in an oxygen atmosphere, and metal oxides of various stoichiometric composition can be formed on different substrates. We report here on a series of experiments on metal oxide formation by cathodic arc deposition for different applications. Black copper oxide has been deposited on ALS components to increase the radiative heat transfer between the parts. Various metal oxides such as tungsten oxide, niobium oxide, nickel oxide and vanadium oxide have been deposited on ITO glass to form electrochromic films for window applications. Tantalum oxide films are of interest for replacing polymer electrolytes. Optical waveguide structures can be formed by refractive index variation using oxide multilayers. We have synthesized multilayers of Al{sub 2}O{sub 3}/Y{sub 2}O{sub 3}/AI{sub 2}O{sub 3}/Si as possible basic structures for passive optoelectronic integrated circuits, and Al{sub 2-x}Er{sub x}O{sub 3} thin films with a variable Er concentration which is a potential component layer for the production of active optoelectronic integrated devices such as amplifiers or lasers at a wavelength of 1.53 {mu}m. Aluminum and chromium oxide films have been deposited on a number of substrates to impart improved corrosion resistance at high temperature. Titanium sub-oxides which are electrically conductive and corrosion resistant and stable in a number of aggressive environments have been deposited on various substrates. These sub-oxides are of great interest for use in electrochemical cells.

  3. Glass Strengthening via High-Intensity Plasma-Arc Heating

    SciTech Connect (OSTI)

    Wereszczak, Andrew A; Harper, David C; Duty, Chad E; Patel, P

    2010-01-01

    The use of a high-intensity plasma-arc lamp was used to irradiate the surface of soda-lime silicate glass tiles to determine if an increase in strength could be achieved. The lamp had a power density of 3500 W/cm2, a processing area of 1 cm x 10 cm, irradiated near-infrared heating at a wavelength between 0.2 1.4 m, and was controlled to unidirectionally sweep across 50-mm-square tiles at a constant speed of 8 mm/s. Ring-on-ring (RoR) equibiaxial flexure and 4 pt uni-directional flexure testings of entire tiles were used to measure and compare failure stress distributions of treated and untreated glass. Even with non-optimized processing conditions, RoR failure stress increased by approximately 25% and the 4 pt bend failure stress increased by approximately 65%. Strengthening was due to a fire-polishing-like mechanism. The arc-lamp heat-treatment caused the location of the strength-limiting flaws in the 4-pt-bend tiles to change; namely, failure initiation occurred on the gage section surface for the treated glass whereas it occurred at a gage section edge for the untreated. Arc-lamp heat-treatment is attractive not only because it provides strengthening, but because it can (non-contact) process large amounts of glass quickly and inexpensively, and is a process that either a glass manufacturer or end-user can readily employ.

  4. Shunting arc plasma source for pure carbon ion beam

    SciTech Connect (OSTI)

    Koguchi, H.; Sakakita, H.; Kiyama, S.; Shimada, T.; Sato, Y.; Hirano, Y.

    2012-02-15

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA/mm{sup 2} at the peak of the pulse.

  5. Formation of carbon deposits from coal in an arc plasma

    SciTech Connect (OSTI)

    Wang, B.; Tian, Y.; Zhang, Y.; Zhu, S.; Lu, Y.; Zhang, Y.; Xie, K.

    2007-07-01

    The issue of deposited carbon (DC) on a reactor wall during the production of acetylene by the coal/arc plasma process is a potential obstacle for the industrialization process. The formation mechanism of DC is very difficult to reveal because the high complexity of coal and the volatile matter. Combining with quenching technique, the methane, liquid petroleum gas and benzene were employed as the model materials to roughly act as the light gas, chain and aromatic subcomponents of volatile matter, and then the reasonable formation mechanism of DC was subtly speculated accordingly.

  6. Origin of basalts by hybridisation in andesite-dominated arcs

    E-Print Network [OSTI]

    Cassidy, Michael; Edmonds, Marie; Watt, Sebastian F. L.; Palmer, Martin R.; Gernon, Thomas M.

    2015-02-16

    seen in the erupted magmas 428 (Cashman and Blundy, 2013). These authors suggest that magma storage systems under most 429 arc volcanoes are dominated by similar processes, where crystal mushes are fed by hotter, 430 slightly more mafic magma... (most common) and reverse zoning at the 476 rim of the crystal (Figs. 5c, 6, 7 and 12a). Many of the Group 1 olivines exhibit normal 477 zoning at the rims, consistent with magma from a primitive mush entrained into a more 478 evolved storage system...

  7. Advanced RenewableEnergy Company ARC Energy | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION JEnvironmental Jump to:EAand DaltonSolar Energy LLCAdema TechnologiesRenewableEnergy Company ARC

  8. Neutral beam dump with cathodic arc titanium gettering

    SciTech Connect (OSTI)

    Smirnov, A.; Korepanov, S. A.; Putvinski, S.; Krivenko, A. S.; Murakhtin, S. V.; Savkin, V. Ya.

    2011-03-15

    An incomplete neutral beam capture can degrade the plasma performance in neutral beam driven plasma machines. The beam dumps mitigating the shine-through beam recycling must entrap and retain large particle loads while maintaining the beam-exposed surfaces clean of the residual impurities. The cathodic arc gettering, which provides high evaporation rate coupled with a fast time response, is a powerful and versatile technique for depositing clean getter films in vacuum. A compact neutral beam dump utilizing the titanium arc gettering was developed for a field-reversed configuration plasma sustained by 1 MW, 20-40 keV neutral hydrogen beams. The titanium evaporator features a new improved design. The beam dump is capable of handling large pulsed gas loads, has a high sorption capacity, and is robust and reliable. With the beam particle flux density of 5 x 10{sup 17} H/(cm{sup 2}s) sustained for 3-10 ms, the beam recycling coefficient, defined as twice the ratio of the hydrogen molecular flux leaving the beam dump to the incident flux of high-energy neutral atoms, is {approx}0.7. The use of the beam dump allows us to significantly reduce the recycling of the shine-through neutral beam as well as to improve the vacuum conditions in the machine.

  9. Ion velocities in a micro-cathode arc thruster

    SciTech Connect (OSTI)

    Zhuang Taisen; Shashurin, Alexey; Keidar, Michael; Beilis, Isak

    2012-06-15

    Ion velocities in the plasma jet generated by the micro-cathode arc thruster are studied by means of time-of-flight method using enhanced ion detection system (EIDS). The EIDS triggers perturbations (spikes) on arc current waveform, and the larger current in the spike generates denser plasma bunches propagating along with the mainstream plasma. The EIDS utilizes double electrostatic probes rather than single probes. The average Ti ion velocity is measured to be around 2 Multiplication-Sign 10{sup 4} m/s without a magnetic field. It was found that the application of a magnetic field does not change ion velocities in the interelectrode region while leads to ion acceleration in the free expanding plasma plume by a factor of about 2. Ion velocities of about 3.5 Multiplication-Sign 10{sup 4} m/s were detected for the magnetic field of about 300 mT at distance of about 100-200 mm from the cathode. It is proposed that plasma is accelerated due to Lorentz force. The average thrust is calculated using the ion velocity measurements and the cathode mass consumption rate, and its increase with the magnetic field is demonstrated.

  10. Material-dependent high-frequency current fluctuations of cathodic vacuum arcs: Evidence for the ecton cutoff of the fractal model

    E-Print Network [OSTI]

    Anders, Andre; Oks, Efim

    2005-01-01

    phenomena. However, spot and arc plasma phenomena are non-short coaxial cathodic arc plasma source was flange-mountedin the expanding plasma 4 , and the arc burning voltage

  11. SU-E-T-568: Improving Normal Brain Sparing with Increasing Number of Arc Beams for Volume Modulated Arc Beam Radiosurgery of Multiple Brain Metastases

    SciTech Connect (OSTI)

    Hossain, S; Hildebrand, K; Ahmad, S; Larson, D; Ma, L; Sahgal, A

    2014-06-01

    Purpose: Intensity modulated arc beams have been newly reported for treating multiple brain metastases. The purpose of this study was to determine the variations in the normal brain doses with increasing number of arc beams for multiple brain metastases treatments via the TrueBeam Rapidarc system (Varian Oncology, Palo Alto, CA). Methods: A patient case with 12 metastatic brain lesions previously treated on the Leksell Gamma Knife Perfexion (GK) was used for the study. All lesions and organs at risk were contoured by a senior radiation oncologist and treatment plans for a subset of 3, 6, 9 and all 12 targets were developed for the TrueBeam Rapidarc system via 3 to 7 intensity modulated arc-beams with each target covered by at least 99% of the prescribed dose of 20 Gy. The peripheral normal brain isodose volumes as well as the total beam-on time were analyzed with increasing number of arc beams for these targets. Results: All intensisty modulated arc-beam plans produced efficient treatment delivery with the beam-on time averaging 0.6–1.5 min per lesion at an output of 1200 MU/min. With increasing number of arc beams, the peripheral normal brain isodose volumes such as the 12-Gy isodose line enclosed normal brain tissue volumes were on average decreased by 6%, 11%, 18%, and 28% for the 3-, 6-, 9-, 12-target treatment plans respectively. The lowest normal brain isodose volumes were consistently found for the 7-arc treatment plans for all the cases. Conclusion: With nearly identical beam-on times, the peripheral normal brain dose was notably decreased when the total number of intensity modulated arc beams was increased when treating multiple brain metastases. Dr Sahgal and Dr Ma are currently serving on the board of international society of stereotactic radiosurgery.

  12. Small and mesoscale properties of a substorm onset auroral arc H. U. Frey,1

    E-Print Network [OSTI]

    California at Berkeley, University of

    Small and mesoscale properties of a substorm onset auroral arc H. U. Frey,1 O. Amm,2 C. C. Chaston; revised 22 June 2010; accepted 28 June 2010; published 7 October 2010. [1] We present small and mesoscale. Good agreement could be reached for the mesoscale arc properties. A qualitative analysis

  13. Arc Fault Signal Detection -Fourier Transformation vs. Wavelet Decomposition Techniques using Synthesized Data

    E-Print Network [OSTI]

    for reliable and safe system operation and is a prerequisite for widespread adoption of PV generation systems Abstract -- Arc faults are a significant reliability and safety concern for photovoltaic (PV) systems is that arc faults in the PV systems do not happen predictably, and depending on the location of the sensors

  14. Temporal evolution characteristics of an annular-mode gliding arc discharge in a vortex flow

    SciTech Connect (OSTI)

    Zhao, Tian-Liang; Liu, Jing-Lin; Li, Xiao-Song; Liu, Jin-Bao; Song, Yuan-Hong; Xu, Yong; Zhu, Ai-Min

    2014-05-15

    An annular-mode gliding arc discharge powered by a 50?Hz alternating current (ac) supply was studied in a vortex flow of dry and humid air. Its temporal evolution characteristics were investigated by electrical measurement, temporally resolved imaging, and temporally resolved optical emission spectroscopic measurements. Three discharge stages of arc-ignition, arc-gliding, and arc-extinction were clearly observed in each half-cycle of the discharge. During the arc-gliding stage, the intensity of light emission from the arc root at the cathode was remarkably higher than that at other areas. The spectral intensity of N{sub 2}(C{sup 3}?{sub u}?B{sup 3}?{sub g}) during the arc-ignition stage was much higher than that during the arc-gliding stage, which was contrary to the temporal evolutions of spectral intensities for N{sub 2}{sup +}(B{sup 2}?{sub u}{sup +}?X{sup 2}?{sub g}{sup +}) and OH(A{sup 2}?{sup +}?X{sup 2}?{sub i}). Temporally resolved vibrational and rotational temperatures of N{sub 2} were also presented and decreased with increasing the water vapor content.

  15. Shear-flow excitation mechanisms of recessed localized arc-filament plasma actuators

    E-Print Network [OSTI]

    Freund, Jonathan B.

    Shear-flow excitation mechanisms of recessed localized arc-filament plasma actuators R. R. Kleinman Received 29 April 2010; accepted 23 September 2010; published online 16 November 2010 Localized arc-filament plasma actuators, placed near the nozzle lip of a laboratory jet, have recently been demonstrated to have

  16. Method and device for reducing overpenetration at the start of plasma arc welds

    SciTech Connect (OSTI)

    Sanders, J.M.; Lehmann, J.M.; Ryan, P.M.

    2000-03-14

    A shim for improving plasma arc weld quality has ends tapered at about 25{degree} and notches at each end roughly centered over the corner between the tapered ends and main body of the shim. The improved shim allows lower starting plasma arc heat input and reduces the occurrence of sagging, or overpenetration, of the weld.

  17. Evaluation Method for Arc Fault Detection Algorithms Stephen McConnell1

    E-Print Network [OSTI]

    Laboratories, Albuquerque, New Mexico, 87185, USA Abstract -- Many methods have been proposed to detect arc for the ubiquitous use of arc fault detectors in photovoltaic arrays [1]. Without these devices, solar arrays remain in representing a host of real-world PV systems? Every solar array tied to the grid contains an electric

  18. The giant luminous arc Statistics. II. spherical lens models based on ROSAT HRI data

    E-Print Network [OSTI]

    Kohji Molikawa; Makoto Hattori; Jean-Paul Kneib; Kazuyuki Yamashita

    1999-09-10

    We present ROSAT HRI X-ray observations of all the galaxy clusters in the Le F\\`evre et al. arc survey sample in order to study the spatial distribution of the intra-cluster medium, and examine the expected number of giant luminous arcs for the sample using two spherically symmetric lens models constrained by our X-ray data.

  19. Review Article Timing of collision of the KohistanLadakh Arc with India

    E-Print Network [OSTI]

    Seno, Tetsuzo

    Review Article Timing of collision of the Kohistan­Ladakh Arc with India and Asia: Debateiar_774 was regarded as of Jurassic­Cretaceous age and was welded to Asia and India by Northern and Southern Sutures respectively. Formation of this arc, timings of its collisions with Asia and India, and position of collision

  20. Method and device for reducing overpenetration at the start of plasma arc welds

    DOE Patents [OSTI]

    Sanders, John M. (Jackson Township, Stark County, OH); Lehmann, John M. (Bedford County, VA); Ryan, Patrick M. (Washington Township, Stark County, OH)

    1998-01-01

    A shim for improving plasma arc weld quality has ends tapered at about 25.degree. and notches at each end roughly centered over the corner between the tapered ends and main body of the shim. The improved shim allows lower starting plasma arc heat input and reduces the occurrence of sagging, or overpenetration, of the weld.

  1. Memory-influencing intra-basolateral amygdala drug infusions modulate expression of Arc

    E-Print Network [OSTI]

    O'Toole, Alice J.

    Memory-influencing intra-basolateral amygdala drug infusions modulate expression of Arc protein processes. Infusions of the -adrenoreceptor agonist, clen- buterol, into the BLA immediately after training increased Arc protein levels in the dorsal hippocampus. Additionally, posttraining intra-BLA infusions

  2. ARC: An Integrated Admission and Rate Control Framework for CDMA Data Networks Based on

    E-Print Network [OSTI]

    Chatterjee, Mainak

    strategy set so as to maximize the utility (revenue) yet at- taining its target churn rate (the probabilityARC: An Integrated Admission and Rate Control Framework for CDMA Data Networks Based on Non this perspective, we propose an integrated admission and rate control (ARC) framework for CDMA based wire- less

  3. Visible Light Emissions during Gas Tungsten Arc Welding and Its Application to Weld

    E-Print Network [OSTI]

    Eagar, Thomas W.

    \\ Visible Light Emissions during Gas Tungsten· Arc Welding and Its Application to Weld Image. EAGAR ABSTRACT. An experimental study was carried out to map the light emissions from a gas tungsten arc. The emissions were found to be dramat- ically different with different shielding gases, welding current and base

  4. Development/Plasticity/Repair A Specific Requirement of Arc/Arg3.1 for Visual

    E-Print Network [OSTI]

    Lee, Hey-Kyoung

    Development/Plasticity/Repair A Specific Requirement of Arc/Arg3.1 for Visual Experience-Induced Homeostatic Synaptic Plasticity in Mouse Primary Visual Cortex Ming Gao,1 Kenneth Sossa,1 Lihua Song,1 Lauren.OurresultsdemonstratethatArc/Arg3.1playsaselectiveroleinregulatingvisualexperience-dependent homeostatic plasticity of excitatory

  5. Enigmatic formation of the Norfolk Basin, SW Pacific: A plume influence on back-arc extension

    E-Print Network [OSTI]

    Müller, Dietmar

    Enigmatic formation of the Norfolk Basin, SW Pacific: A plume influence on back-arc extension Maria Jussieu Paris cedex 5, France (alain.mauffret@lgs.jussieu.fr) George Bernardel Geoscience Australia, Cnr] The Norfolk Basin is a small back-arc basin in the SW Pacific with an unknown age and origin for its formation

  6. Electrical Circuit Flashover Model of Polluted Insulators under AC Voltage Based on the Arc Root Voltage Gradient Criterion

    E-Print Network [OSTI]

    Yang, Qing

    In order to study the flashover mechanism of polluted insulators under AC voltage, a new arc propagation criterion which is based on an arc root voltage gradient is proposed. This criterion can explain the variation of the ...

  7. Can surface cracks and unipolar arcs explain breakdown and gradient limits?

    SciTech Connect (OSTI)

    Insepov, Zeke; Norem, Jim

    2013-01-15

    The authors argue that the physics of unipolar arcs and surface cracks can help understand rf breakdown and vacuum arc data. They outline a model of the basic mechanisms involved in breakdown and explore how the physics of unipolar arcs and cracks can simplify the picture of breakdown and gradient limits in accelerators, tokamaks as well as laser ablation, micrometeorites, and other applications. Cracks are commonly seen in SEM images of arc damage and they are produced as the liquid metal cools. They can produce the required field enhancements to explain field emission data and can produce mechanical failure of the surface that would trigger breakdown events. Unipolar arcs can produce currents sufficient to short out rf structures, and can cause the sort of damage seen in SEM images. They should be unstable, and possibly self-quenching, as seen in optical fluctuations and surface damage. The authors describe some details and consider the predictions of this simple model.

  8. Correlation between cathode properties, burning voltage, and plasma parameters of vacuum arcs

    SciTech Connect (OSTI)

    Anders, Andre; Yotsombat, Banchob; Binder, Robert

    2001-06-15

    Burning voltages of vacuum arcs were measured for 54 cathode materials and compared with literature data. As anticipated, a correlation between the arc burning voltage and the plasma temperature was found. However, more importantly, a correlation between the cohesive energy of the cathode material and the arc burning voltage could be demonstrated. This link between a cathode material property, the cohesive energy, and a discharge property, the arc burning voltage, is essential for the operation of the vacuum arc discharge because is determines the plasma temperature. Energy balance considerations show that this {open_quotes}cohesive energy rule{close_quotes} is responsible for several other secondary relationships, such as the correlation between the mean ion charge state and the boiling temperature of the cathode. {copyright} 2001 American Institute of Physics.

  9. ArcGIS tools for streamlining habitat map data integrationArcGIS tools for streamlining habitat map data integration Paul Jessop, Chris Goldfinger, Chris RomsosPaul Jessop, Chris Goldfinger, Chris Romsos

    E-Print Network [OSTI]

    Goldfinger, Chris

    ArcGIS tools for streamlining habitat map data integrationArcGIS tools for streamlining habitat map. In addressing these problems, we are developing ArcGIS tools that streamline the regeneration of data quality navigation). The data quality tools encapsulate and automate specific processing steps used to create ranked

  10. Charge to the External Review Committee for the NSTX-U Arc Fault During the commissioning of NSTX-U for its first test plasma, an arc took place in its

    E-Print Network [OSTI]

    Princeton Plasma Physics Laboratory

    -U for its first test plasma, an arc took place in its Ohmic heating circuit inflicting significant damageCharge to the External Review Committee for the NSTX-U Arc Fault During the commissioning of NSTX questions below. 1. Technical cause: Are the causes for the arc correctly identified and understood

  11. Probe characterization of high-current driven metal plasma in a vacuum-arc rail gun

    SciTech Connect (OSTI)

    Vijayan, T.; Roychowdhury, P.; Venkatramani, N.

    2004-10-15

    The characteristics of metal plasma launched by high-current electric arc in a vacuum-arc rail gun are determined by employing electrical and magnetic probes. These measurements are validated by results from theoretical simulations. The arc coupled nonlinear circuit equations are solved simultaneously with the Newtonian arc motion and revealed the undercritically damped behavior of the arc current identical to the arc-current signal recorded by the Rogowski magnetic probe. Similarly the arc velocity and displacement derived from the signatures of B-dot probes are shown to concur closely with the results of JxB propulsion from simulation. The heating of plasma is formulated in a three-electron population regime with direct arc energy coupling through magnetohydrodynamic, ion-acoustic, Coulomb, and neutral interactions. This results in high temperature (T{sub e}) of hundreds of eV in the arc as revealed by the simulation. Hence T{sub e} of the rapidly cooling and equilibrating plasma that emerged from the muzzle is high around 80-90 eV, which is confirmed by Langmuir electric probe measurements. Density n{sub e} of this metal plasma is shown to be in the range 4x10{sup 21}-6x10{sup 21} m{sup -3} and includes multiple ion charge states. The exit velocity of the plasma measured by a pair of Langmuir probes is close to 2.2x10{sup 6} cm/s and matched well with the arc velocity determined by the B-dot probes and the results from simulation.

  12. A comparison of the marginal adaptation of cathode-arc vapor-deposited titanium and cast base metal copings.

    E-Print Network [OSTI]

    Wu, Jean C; Lai, Li-Chung; Sheets, Cherilyn G; Earthman, James; Newcomb, Robert

    2011-01-01

    thick, dark titanium oxide layer. The new cathode-arc vaporcolor of the titanium oxide layer resulted in compromised

  13. Study of JET Soft Housekeeping Waste Volume Reduction by Plasma Arc Centrifuge and Gasification in Countercurrent Regime Methods

    E-Print Network [OSTI]

    Study of JET Soft Housekeeping Waste Volume Reduction by Plasma Arc Centrifuge and Gasification in Countercurrent Regime Methods

  14. Nature of high-energy ions in the cathode plasma jet of a vacuum arc with high rate of current rise

    SciTech Connect (OSTI)

    Beilis, I.I.

    2004-10-04

    The production mechanism of extremely high-energy (up to 10 keV) ions observed in vacuum arcs having only a few tens of volts of arc voltage was considered. A model was developed for the plasma acceleration in a high-current ({>=}1 kA) short pulsed (<1 {mu}s) vacuum arc, taking into account the high rate of rise of the spot current (dI/dt>100 MA/s). A system of equations, including equations for the cathode spot and the plasma jet, was solved self-consistently with dI/dt in the range of 0.1-10 GA/s. It was shown that the plasma could be accelerated to the measured energy in the near spot region due to a gas dynamic mechanism and that the ion energy depends on the ratio of the ion flux to the electron flux. This ratio is determined by the cathode erosion rate. The calculated cathode erosion rate varies from 200 to 10 {mu}g/C when the ion energy increases from 0.1 to 10 keV and well agrees with measurements.

  15. ARC Photovoltaics Centre of Excellence 2009 A n n u a l R e p o r t

    E-Print Network [OSTI]

    New South Wales, University of

    ARC Photovoltaics Centre of Excellence 2009 A n n u a l R e p o r t #12;ARC Photovoltaics Centre of Excellence #12;ARC Photovoltaics Centre of Excellence 1 2009 Annual Report Contents Section______________________________________________________134 8. Publications____________________________________________________________136 #12;PHOTOVOLTAICS

  16. Mechanism of surface modification in the plasma-surface interaction in electrical arcs CERN, CH-1211 Genve 23, Switzerland

    E-Print Network [OSTI]

    Nordlund, Kai

    Mechanism of surface modification in the plasma-surface interaction in electrical arcs H. Timko received 22 February 2010; published 25 May 2010 Electrical sparks and arcs are plasma discharges the given conditions in the plasma sheath to kiloelectron volt energies, on surfaces. The flux in arcs is so

  17. Dilution Control in Gas-Tungsten-Arc Welds Involving Superaustenitic Stainless Steels and Nickel-Based Alloys

    E-Print Network [OSTI]

    DuPont, John N.

    ) were produced by varying the independent welding parameters of arc power and volumetric filler and decreasing arc power. These effects are quantitatively interpreted based on a previously proposed processing be correlated exclusively to the ratio of the volumetric filler-metal feed rate (Vfm) to arc power (VI), i

  18. ELLIPTIC ARC VECTORIZATION FOR 3D PIE CHART RECOGNITION Weihua Huang, Chew Lim Tan and Wee Kheng Leow

    E-Print Network [OSTI]

    Leow, Wee Kheng

    ELLIPTIC ARC VECTORIZATION FOR 3D PIE CHART RECOGNITION Weihua Huang, Chew Lim Tan and Wee Kheng, we present a novel approach to vectorize elliptic arcs for 3D pie chart recognition and data elliptic arcs are the key components in the 3D pie charts that allow us to determine the chart type

  19. Inferring crustal structure in the Aleutian island arc from a sparse wide-angle seismic data set

    E-Print Network [OSTI]

    Shillington, Donna J.

    in the Aleutian islands shed a new light on island arc systems, and the role that magmatic arcs may play G 3 G 3Inferring crustal structure in the Aleutian island arc from a sparse wide-angle seismic data set inversion with static corrections for island stations reduces the data variance of a 1-D starting model

  20. Gas-tungsten arc welding of aluminum alloys

    DOE Patents [OSTI]

    Frye, L.D.

    1982-03-25

    The present invention is directed to a gas-tungsten arc welding method for joining together structures formed of aluminum alloy with these structures disposed contiguously to a heat-damagable substrate of a metal dissimilar to the aluminum alloy. The method of the present invention is practiced by diamond machining the fay surfaces of the aluminum alloy structures to profice a mirror finish thereon having a surface roughness in the order of about one microinch. The fay surface are aligned and heated sufficiently by the tungsten electrode to fuse the aluminum alloy continguous to the fay surfaces to effect the weld joint. The heat input used to provide an oxide-free weld is significantly less than that required if the fay surfaces were prepared by using conventional chemical and mechanical practices.

  1. Method of operating a centrifugal plasma arc furnace

    DOE Patents [OSTI]

    Kujawa, S.T.; Battleson, D.M.; Rademacher, E.L. Jr.; Cashell, P.V.; Filius, K.D.; Flannery, P.A.; Whitworth, C.G.

    1998-03-24

    A centrifugal plasma arc furnace is used to vitrify contaminated soils and other waste materials. An assessment of the characteristics of the waste is performed prior to introducing the waste into the furnace. Based on the assessment, a predetermined amount of iron is added to each batch of waste. The waste is melted in an oxidizing atmosphere into a slag. The added iron is oxidized into Fe{sub 3}O{sub 4}. Time of exposure to oxygen is controlled so that the iron does not oxidize into Fe{sub 2}O{sub 3}. Slag in the furnace remains relatively non-viscous and consequently it pours out of the furnace readily. Cooled and solidified slag produced by the furnace is very resistant to groundwater leaching. The slag can be safely buried in the earth without fear of contaminating groundwater. 3 figs.

  2. Method of operating a centrifugal plasma arc furnace

    DOE Patents [OSTI]

    Kujawa, Stephan T. (Butte, MT); Battleson, Daniel M. (Butte, MT); Rademacher, Jr., Edward L. (Butte, MT); Cashell, Patrick V. (Butte, MT); Filius, Krag D. (Butte, MT); Flannery, Philip A. (Ramsey, MT); Whitworth, Clarence G. (Butte, MT)

    1998-01-01

    A centrifugal plasma arc furnace is used to vitrify contaminated soils and other waste materials. An assessment of the characteristics of the waste is performed prior to introducing the waste into the furnace. Based on the assessment, a predetermined amount of iron is added to each batch of waste. The waste is melted in an oxidizing atmosphere into a slag. The added iron is oxidized into Fe.sub.3 O.sub.4. Time of exposure to oxygen is controlled so that the iron does not oxidize into Fe.sub.2 O.sub.3. Slag in the furnace remains relatively non-viscous and consequently it pours out of the furnace readily. Cooled and solidified slag produced by the furnace is very resistant to groundwater leaching. The slag can be safely buried in the earth without fear of contaminating groundwater.

  3. Arc plasma simulation of the KAERI large ion source

    SciTech Connect (OSTI)

    In, S. R.; Jeong, S. H.; Kim, T. S.

    2008-02-15

    The KAERI large ion source, developed for the KSTAR NBI system, recently produced ion beams of 100 keV, 50 A levels in the first half campaign of 2007. These results seem to be the best performance of the present ion source at a maximum available input power of 145 kW. A slight improvement in the ion source is certainly necessary to attain the final goal of an 8 MW ion beam. Firstly, the experimental results were analyzed to differentiate the cause and effect for the insufficient beam currents. Secondly, a zero dimensional simulation was carried out on the ion source plasma to identify which factors control the arc plasma and to find out what improvements can be expected.

  4. Quantitative characterization of arc discharge as vacuum interface

    SciTech Connect (OSTI)

    Huang, S.; Zhu, K.; Lu, Y. R.; Wang, S. Z.; Hershcovitch, A.; Yang, L.; Zhang, X. Y.

    2014-12-19

    An arc discharge with channel diameters of 3 mm and 6 mm and lengths between 30mm and 60mm was experimentally investigated for its potential to function as plasma window, i.e., interface vacuum regions of different pressures. In this study, electron temperature of the plasma channel measured spectroscopically varied in the range of 7000K to 15000K, increasing with discharge current while decreasing with gas flow rate. The plasma window had a slightly positive I-V characteristics over the whole range of investigated current 30A–70 A. Measurements of pressure separation capability, which were determined by input current, gas flow rate, discharge channel diameter, and length, were well explained by viscosity effect and “thermal-block” effect. The experimental results of global parameters including temperature, gas flow rate, and voltage had a good agreement with the simulation results calculated by an axis-symmetry Fluent-based magneto-hydrodynamic model.

  5. Quantitative characterization of arc discharge as vacuum interface

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Huang, S.; Zhu, K.; Lu, Y. R.; Wang, S. Z.; Hershcovitch, A.; Yang, L.; Zhang, X. Y.

    2014-12-19

    An arc discharge with channel diameters of 3 mm and 6 mm and lengths between 30mm and 60mm was experimentally investigated for its potential to function as plasma window, i.e., interface vacuum regions of different pressures. In this study, electron temperature of the plasma channel measured spectroscopically varied in the range of 7000K to 15000K, increasing with discharge current while decreasing with gas flow rate. The plasma window had a slightly positive I-V characteristics over the whole range of investigated current 30A–70 A. Measurements of pressure separation capability, which were determined by input current, gas flow rate, discharge channel diameter,more »and length, were well explained by viscosity effect and “thermal-block” effect. The experimental results of global parameters including temperature, gas flow rate, and voltage had a good agreement with the simulation results calculated by an axis-symmetry Fluent-based magneto-hydrodynamic model.« less

  6. Evolution of Holographic Fermi Arcs from a Mott Insulator

    E-Print Network [OSTI]

    Garrett Vanacore; Srinidhi T. Ramamurthy; Philip W. Phillips

    2015-08-10

    We study fermions in an electrically-probed and asymptotically anti-de Sitter Schwarzschild spacetime which interact via a novel chiral symmetry-preserving interaction. Computing the dual fermion two-point correlator, we show that this bulk interaction anisotropically gaps Fermi surfaces of the boundary spectrum. Consequently, the interaction we devise provides a holographic model for Fermi arcs seen ubiquitously in the pseudogap regime of the cuprates. Our interaction is a modification of the chiral symmetry-breaking Pauli coupling, which has previously been proposed as the holographic realization of Mott physics. The onset of Mott insulation and pseudogap physics are respectively discussed in the context of bulk chiral and boundary parity symmetry breaking, and the Mott transition is interpreted as a deconfinement transition of non-Fermi liquid excitations.

  7. Evolution of Holographic Fermi Arcs from a Mott Insulator

    E-Print Network [OSTI]

    Vanacore, Garrett; Phillips, Philip W

    2015-01-01

    We study fermions in an electrically-probed and asymptotically anti-de Sitter Schwarzschild spacetime which interact via a novel chiral symmetry-preserving interaction. Computing the dual fermion two-point correlator, we show that this bulk interaction anisotropically gaps Fermi surfaces of the boundary spectrum. Consequently, the interaction we devise provides a holographic model for Fermi arcs seen ubiquitously in the pseudogap regime of the cuprates. Our interaction is a modification of the chiral symmetry-breaking Pauli coupling, which has previously been proposed as the holographic realization of Mott physics. The onset of Mott insulation and pseudogap physics are respectively discussed in the context of bulk chiral and boundary parity symmetry breaking, and the Mott transition is interpreted as a deconfinement transition of non-Fermi liquid excitations.

  8. Fourier-transform microwave spectroscopy and determination of the three dimensional potential energy surface for Ar–CS

    SciTech Connect (OSTI)

    Niida, Chisato; Nakajima, Masakazu; Endo, Yasuki; Sumiyoshi, Yoshihiro; Ohshima, Yasuhiro; Kohguchi, Hiroshi

    2014-03-14

    Pure rotational transitions of the Ar–CS van der Waals complex have been observed by Fourier Transform Microwave (FTMW) and FTMW-millimeter wave double resonance spectroscopy. Rotational transitions of v{sub s} = 0, 1, and 2 were able to be observed for normal CS, together with those of C{sup 34}S in v{sub s} = 0, where v{sub s} stands for the quantum number of the CS stretching vibration. The observed transition frequencies were analyzed by a free rotor model Hamiltonian, where rovibrational energies were calculated as dynamical motions of the three nuclei on a three-dimensional potential energy surface, expressed by analytical functions with 57 parameters. Initial values for the potential parameters were obtained by high-level ab initio calculations. Fifteen parameters were adjusted among the 57 parameters to reproduce all the observed transition frequencies with the standard deviation of the fit to be 0.028 MHz.

  9. Vacuum Arc Plasma Motion In A Curvilinear Magnetic Field In A Framework Of The Rigid-Rotor Model

    SciTech Connect (OSTI)

    Timoshenko, Aleksandr I.; Gnybida, Mikhail V.; Taran, Valeriy S.; Tereshin, Vladimir I.; Chechel'nitskij, Oleg G.

    2006-01-15

    Vacuum-arc plasma motion in a toroidal magnetic field is described on a base of steady-state ({partial_derivative}/{partial_derivative}t = 0) Vlasov-Maxwell equations for the long plasma column aligned parallel to a constant axial magnetic field. The relations for the self-consistent electric field, which appears due to a displacement of the electrons from the ions at the curvilinear trajectory, were derived within a framework of the drift approximation. The dynamics of the central part of the plasma flow in the electric polarization fields was considered in detail. The displacement of the plasma flow at the output of the plasma duct was calculated. The results are in a good agreement with the experimental data obtained by others authors.

  10. Current constriction of high-current vacuum arc in vacuum interrupters

    SciTech Connect (OSTI)

    Wang Lijun; Jia Shenli; Zhang Ling; Yang Dingge; Shi Zongqian; Gentils, Francois; Jusselin, Benoit

    2008-03-15

    Compared with previous paper [L. Wang et al., J. Appl. Phys. 100, 113304 (2006)], higher-current vacuum arc is simulated and analyzed based on magnetohydrodynamics model, and current constriction phenomenon in arc column is mainly paid attention to and analyzed in this paper. According to simulation results, it can be found that significant current constriction only appears near anode regions for lower-current vacuum arc. However, with the increase of arc current, current constriction also appears near the cathode side, and with the further increase of arc current, current constriction near the cathode side can become more significant than that near the anode side. The current constriction near the cathode side can be mainly caused by very high current level. The increase of axial magnetic field (AMF) strength will inhibit current constriction in the whole arc column. For influence of AMF distribution, saddle-shaped distributed AMF can more efficiently inhibit current constriction of arc column than bell-shaped AMF. The phenomenon of current constriction near the cathode side has also been found by many experiments, which also can verify the correctness of simulation results.

  11. Arc discharge regulation of a megawatt hot cathode bucket ion source for the experimental advanced superconducting tokamak neutral beam injector

    SciTech Connect (OSTI)

    Xie Yahong; Hu Chundong; Liu Sheng; Jiang Caichao; Li Jun; Liang Lizhen; Collaboration: NBI Team

    2012-01-15

    Arc discharge of a hot cathode bucket ion source tends to be unstable what attributes to the filament self-heating and energetic electrons backstreaming from the accelerator. A regulation method, which based on the ion density measurement by a Langmuir probe, is employed for stable arc discharge operation and long pulse ion beam generation. Long pulse arc discharge of 100 s is obtained based on this regulation method of arc power. It establishes a foundation for the long pulse arc discharge of a megawatt ion source, which will be utilized a high power neutral beam injection device.

  12. Modeling And Measurements Of The Arc Plasma In A Mixture Of Gases

    SciTech Connect (OSTI)

    Pawelec, E.; KsiaPzek, I.

    2006-01-15

    Radial distributions of Ar mass fractions and temperatures in plasmas produced in a wall-stabilized arc have been calculated. Modeling have been performed for many different mixtures of Ar+N2 and three different arc currents. The obtained results show that the radial distributions of Ar mass fractions strongly depend on the chemical composition of the plasma. In plasmas containing large amount of Ar the distributions have local minima at the arc axis (in high temperature plasma regions), whereas in plasmas consisting mainly of nitrogen the distributions reveal maxima on the discharge axis. Those features seem to be connected with the dissociation of the nitrogen.

  13. Arc Detection and Interlock Module for the PEP II Low Level RF System

    SciTech Connect (OSTI)

    Tighe, R.; /SLAC

    2011-08-31

    A new arc detection and interlock generating module for the SLAC PEP-II low-level RF VXI-based system has been developed. The system is required to turn off the RF drive and high voltage power supply in the event of arcing in the cavity windows, klystron window, or circulator. Infrared photodiodes receive arc signals through radiation resistant optical fibers. Gain and bandwidth are selectable for each channel to allow tailoring response. The module also responds to interlock requests from other modules in the VXI system and communicates with the programmable logic controller (PLC) responsible for much of the low-level RF system's interlock functionality.

  14. Sci—Sat AM: Stereo — 03: Dosmetric evaluation of single versus multi-arc VMAT for lung SBRT

    SciTech Connect (OSTI)

    Karan, T; Taremi, M; Comsa, D; Allibhai, Z; Ryan, M; Le, K

    2014-08-15

    Five non-small cell lung cancer patients previously treated with stereotactic body radiation therapy using the VMAT (volumetric modulated arc therapy) technique were selected for this retrospective study. Plans were re-optimized using Pinnacle treatment planning system (v9.0, Philips Medical), with the basis for comparison a two-arc plan involving a 360° arc in addition to a 90° arc with a couch kick. Additionally a single 360° arc was optimized for comparison, as well as a partial arc covering ?230°, avoiding the contralateral lung. All plans met target coverage criteria as dictated by RTOG0236. Plans were evaluated based on conformity, sparing of organs at risk and practical considerations of delivery. Conformity was best in the two-arc plan; however the decrease seen in one- and partial arc plans was not statistically significant as tested by the Wilcoxon rank sum test. The partial-arc plan resulted in the lowest esophagus and trachea dose and the highest heart dose, however none of the plans exceeded organ at risk tolerances for lung SBRT. Partial arcs resulted in plans with slightly cooler dose distributions, a decrease in low dose spillage and an overall lower mean lung dose. The decrease in treatment time was on average 36 and 40 seconds for single and partial arcs, respectively, with partial arcs requiring the lowest number of MUs. The slight decrease in conformity seen in one-arc plans is offset by an increase in efficiency (optimization and treatment time, MUs) making the implementation of a single or partial-arc treatment technique clinically desirable.

  15. Characterizing Fire Danger from Low-Power Photovoltaic Arc-Faults Kenneth M. Armijo, Jay Johnson, Michael Hibbs and Armando Fresquez

    E-Print Network [OSTI]

    capacity of photovoltaic systems continues to grow and age, the number of arc-faults in PV systemsCharacterizing Fire Danger from Low-Power Photovoltaic Arc-Faults Kenneth M. Armijo, Jay Johnson -- While arc-faults are rare in photovoltaic installations, more than a dozen documented arc-faults have

  16. Probing Atomic-Scale Properties of Magnetic and Optoelectronic Nanostructures

    E-Print Network [OSTI]

    Zhang, Xiaowei

    2012-01-01

    1.1.1 Magnetic Molecules for Spintronics Applications 1.1.2Wernsdorfer. Molecular spintronics using single-moleculeEdges: Basis for Novel Spintronics Devices. Phys. Rev. Lett.

  17. Measurement of Transient Atomic-scale Displacements in Thin Films...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    with the (003), (222) and (220) reflections, respectively, collected in the short-pulse low-a mode. The inset shows a streak camera measurement of the x-ray pulse duration....

  18. Atomic Scale Imaging of the Electronic Structure and Chemistry...

    Office of Scientific and Technical Information (OSTI)

    Imaging of the Electronic Structure and Chemistry of Graphene and Its Precursors on Metal Surfaces Re-direct Destination: Executive Summary of Final Report for Award...

  19. Atomic-scale Structural Characterizations of Functional Epitaxial Thin Films 

    E-Print Network [OSTI]

    Zhu, Yuanyuan

    2013-06-03

    ) heterogeneous systems, the flux-pinning defects at both of conversional YBa2Cu3O7-? (YBCO)/substrate lateral interfaces and vertical interfaces of YBCO&BaSnO3(BSO) nanocomposite films, and the misfit dislocation core configurations of STO/MgO and MgO...

  20. Discovery of novel hydrogen storage materials: an atomic scale

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformation Current HAB PacketDiesel pricesCenter atDirectory Searchablebefore they

  1. Innovative Energy Conservation Through Scrao Pre-heating in an Electric Arc Furnace 

    E-Print Network [OSTI]

    Dicion, A.

    2013-01-01

    This paper will present an innovative energy conservation technology for scrap pre-heating in an Electric Arc Furnace that is being implemented in an industrial facility in Ontario. The objective of the paper is to examine the electrical...

  2. The evolution of ion charge states in cathodic vacuum arc plasmas: a review

    SciTech Connect (OSTI)

    Anders, Andre

    2011-12-18

    Cathodic vacuum arc plasmas are known to contain multiply charged ions. 20 years after “Pressure Ionization: its role in metal vapour vacuum arc plasmas and ion sources” appeared in vol. 1 of Plasma Sources Science and Technology, it is a great opportunity to re-visit the issue of pressure ionization, a non-ideal plasma effect, and put it in perspective to the many other factors that influence observable charge state distributions, such as the role of the cathode material, the path in the density-temperature phase diagram, the “noise” in vacuum arc plasma as described by a fractal model approach, the effects of external magnetic fields and charge exchange collisions with neutrals. A much more complex image of the vacuum arc plasma emerges putting decades of experimentation and modeling in perspective.

  3. Application of electrostatic Langmuir probe to atmospheric arc plasmas producing nanostructures

    SciTech Connect (OSTI)

    Shashurin, A.; Li, J.; Zhuang, T.; Keidar, M.; Beilis, I. I.

    2011-07-15

    The temporal evolution of a high pressure He arc producing nanotubes was considered and the Langmuir probe technique was applied for plasma parameter measurements. Two modes of arc were observed: cathodic arc where discharge is supported by erosion of cathode material and anodic arc which is supported by ablation of the anode packed with carbon and metallic catalysts in which carbon nanotubes are synthesized. Voltage-current (V-I) characteristics of single probes were measured and unusually low ratio of saturation current on positively biased probe to that on negatively biased of about 1-4 was observed. This effect was explained by increase of measured current at the negatively biased probe above the level of ion saturation current due to secondary electron emission from the probe surface. Since utilization of standard collisionless approach to determine plasma parameters from the measured V-I characteristic is not correct, the electron saturation current was used to estimate the plasma density.

  4. Controlling electrode gap during vacuum arc remelting at low melting current

    DOE Patents [OSTI]

    Williamson, R.L.; Zanner, F.J.; Grose, S.M.

    1997-04-15

    An apparatus and method are disclosed for controlling electrode gap in a vacuum arc remelting furnace, particularly at low melting currents. Spectrographic analysis is performed of the metal vapor plasma, from which estimates of electrode gap are derived. 5 figs.

  5. Controlling electrode gap during vacuum arc remelting at low melting current

    DOE Patents [OSTI]

    Williamson, Rodney L. (Albuquerque, NM); Zanner, Frank J. (Sandia Park, NM); Grose, Stephen M. (Glenwood, WV)

    1997-01-01

    An apparatus and method for controlling electrode gap in a vacuum arc remelting furnace, particularly at low melting currents. Spectrographic analysis is performed of the metal vapor plasma, from which estimates of electrode gap are derived.

  6. Improving the System Life of Basic Oxygen and Electric Arc Furnace Hoods, Roofs, and Side Vents

    Broader source: Energy.gov [DOE]

    This factsheet describes the benefits of a high-performance aluminum bronze alloy to basic oxygen furnace and electric arc furnace components such as hoods, roofs, and side vents.

  7. How do I display the Map of Wind Farms csv coordinates in ArcMap...

    Open Energy Info (EERE)

    I display the Map of Wind Farms csv coordinates in ArcMap software? Home > Groups > Geospatial I downloaded the Map of Wind Farms data as a .csv from http:en.openei.orgwiki...

  8. Exhaust-gas measurements from NASAs HYMETS arc jet.

    SciTech Connect (OSTI)

    Miller, Paul Albert

    2010-11-01

    Arc-jet wind tunnels produce conditions simulating high-altitude hypersonic flight such as occurs upon entry of space craft into planetary atmospheres. They have traditionally been used to study flight in Earth's atmosphere, which consists mostly of nitrogen and oxygen. NASA is presently using arc jets to study entry into Mars' atmosphere, which consists of carbon dioxide and nitrogen. In both cases, a wide variety of chemical reactions take place among the gas constituents and with test articles placed in the flow. In support of those studies, we made measurements using a residual gas analyzer (RGA) that sampled the exhaust stream of a NASA arc jet. The experiments were conducted at the HYMETS arc jet (Hypersonic Materials Environmental Test System) located at the NASA Langley Research Center, Hampton, VA. This report describes our RGA measurements, which are intended to be used for model validation in combination with similar measurements on other systems.

  9. Novel Direct Steelmaking by Combining Microwave, Electric Arc, and Exothermal Heating Technologies

    Broader source: Energy.gov [DOE]

    This factsheet describes a project to develop direct steelmaking through the combination of microwave, electric arc, and exothermal heating, a process which is meant to eliminate traditional, intermediate steelmaking steps.

  10. Volatilization and redox testing in a DC arc melter: FY-93 and FY-94

    SciTech Connect (OSTI)

    Grandy, J.D.; Sears, J.W.; Soelberg, N.R.; Reimann, G.A.; McIlwain, M.E.

    1996-07-01

    The purpose of these experiments was to study the dissolution, retention, volatilization, and trapping of transuranic radionuclide elements (TRUs), mixed fission and activation products, and high vapor pressure metals (HVPMS) during processing in a high temperature arc furnace. In all cases, surrogate elements (lanthanides) were used in place of radioactive ones. The experiments were conducted utilizing a small DC arc melter developed at the Idaho National Engineering Laboratory (INEL) Research Center (IRC). The small arc melter was originally developed in 1992 and has been used previously for waste form studies of iron enriched basalt (IEB) and IEB with zirconium and titanium additions (IEB4). Section 3 contains a description of the small arc melter and its operational capabilities are discussed in Chapter 4. The remainder of the document describes each testing program and then discusses results and findings.

  11. GMO Guide: How do I manage my ARC grant? Part 1: What are my ongoing responsibilities?

    E-Print Network [OSTI]

    New South Wales, University of

    1 GMO Guide: How do I manage my ARC grant? Part 1: What are my ongoing responsibilities? This GMO a completed Acceptance Form has been received by the Grants Management Office (GMO), the Funding Agreement

  12. Low pressure arc discharge lamp apparatus with magnetic field generating means

    DOE Patents [OSTI]

    Grossman, M.W.; George, W.A.; Maya, J.

    1987-10-06

    A low-pressure arc discharge apparatus having a magnetic field generating means for increasing the output of a discharge lamp is disclosed. The magnetic field generating means, which in one embodiment includes a plurality of permanent magnets, is disposed along the lamp for applying a constant transverse magnetic field over at least a portion of the positive discharge column produced in the arc discharge lamp operating at an ambient temperature greater than about 25 C. 3 figs.

  13. Asymmetric injection of cathodic arc plasma into a macroparticlefilter

    SciTech Connect (OSTI)

    Anders, Andre; MacGill, Robert A.

    2004-02-11

    The cathodic arc plasmas produced by cathode spots usuallyinclude macroparticles, which is undesirable for many applications. Acommon way of removing macroparticles is to use curved solenoid filterswhich guide the plasma from the source to the substrate. In this work, anarc source with relatively small cathode is used, limiting the possiblelocations of plasma production. The relative position of cathodic arcsource and macroparticle filtered was systematically varied and thefiltered plasma current was recorded. It was found that axis-symmetricplasma injection leads to maximum throughput only if an anode aperturewas used, which limited the plasma to near-axis flow by scraping offplasma at larger angles to the axis. When the anode aperture was removed,more plasma could enter the filter. In this case, maximum filtered ioncurrent was achieved when the plasma was injected off-axis, namely offsetin the direction where the filter is curved. Such behavior wasanticipated because the plasma column in the filter is known to beshifted by ExB and centrifugal drift as well as by non-axis-symmetriccomponents of the magnetic field in the filter entrance and exit plane.The data have implications for plasma transport variations caused bydifferent spot locations on cathodes that are not small compared to thefilter cross section.

  14. Stainless steel submerged arc weld fusion line toughness

    SciTech Connect (OSTI)

    Rosenfield, A.R.; Held, P.R.; Wilkowski, G.M. [Battelle, Columbus, OH (United States)

    1995-04-01

    This effort evaluated the fracture toughness of austenitic steel submerged-arc weld (SAW) fusion lines. The incentive was to explain why cracks grow into the fusion line in many pipe tests conducted with cracks initially centered in SAWS. The concern was that the fusion line may have a lower toughness than the SAW. It was found that the fusion line, Ji. was greater than the SAW toughness but much less than the base metal. Of greater importance may be that the crack growth resistance (JD-R) of the fusion line appeared to reach a steady-state value, while the SAW had a continually increasing JD-R curve. This explains why the cracks eventually turn to the fusion line in the pipe experiments. A method of incorporating these results would be to use the weld metal J-R curve up to the fusion-line steady-state J value. These results may be more important to LBB analyses than the ASME flaw evaluation procedures, since there is more crack growth with through-wall cracks in LBB analyses than for surface cracks in pipe flaw evaluations.

  15. Electrical and thermal finite element modeling of arc faults in photovoltaic bypass diodes.

    SciTech Connect (OSTI)

    Bower, Ward Isaac; Quintana, Michael A.; Johnson, Jay

    2012-01-01

    Arc faults in photovoltaic (PV) modules have caused multiple rooftop fires. The arc generates a high-temperature plasma that ignites surrounding materials and subsequently spreads the fire to the building structure. While there are many possible locations in PV systems and PV modules where arcs could initiate, bypass diodes have been suspected of triggering arc faults in some modules. In order to understand the electrical and thermal phenomena associated with these events, a finite element model of a busbar and diode was created. Thermoelectrical simulations found Joule and internal diode heating from normal operation would not normally cause bypass diode or solder failures. However, if corrosion increased the contact resistance in the solder connection between the busbar and the diode leads, enough voltage potentially would be established to arc across micron-scale electrode gaps. Lastly, an analytical arc radiation model based on observed data was employed to predicted polymer ignition times. The model predicted polymer materials in the adjacent area of the diode and junction box ignite in less than 0.1 seconds.

  16. Temporal Development of Ion Beam Mean Charge State in PulsedVacuum Arc Ion Sources

    SciTech Connect (OSTI)

    Oks, Efim M.; Yushkov, Georgy Yu.; Anders, Andre

    2007-06-21

    Vacuum arc ion sources, commonly also known as "Mevva" ionsources, are used to generate intense pulsed metal ion beams. It is knownthat the mean charge state of the ion beam lies between 1 and 4,depending on cathode material, arc current, arc pulse duration, presenceor absence of magnetic field at the cathode, as well background gaspressure. A characteristic of the vacuum arc ion beam is a significantdecrease in ion charge state throughout the pulse. This decrease can beobserved up to a few milliseconds, until a "noisy" steady-state value isestablished. Since the extraction voltage is constant, a decrease in theion charge state has a proportional impact on the average ion beamenergy. This paper presents results of detailed investigations of theinfluence of arc parameters on the temporal development of the ion beammean charge state for a wide range of cathode materials. It is shown thatfor fixed pulse duration, the charge state decrease can be reduced bylower arc current, higher pulse repetition rate, and reduction of thedistance between cathode and extraction region. The latter effect may beassociated with charge exchange processes in the dischargeplasma.

  17. Formation of Self-Organized Anode Patterns in Arc Discharge Simulations

    E-Print Network [OSTI]

    Juan Pablo Trelles

    2012-12-31

    Pattern formation and self-organization are phenomena commonly observed experimentally in diverse types of plasma systems, including atmospheric-pressure electric arc discharges. However, numerical simulations reproducing anode pattern formation in arc discharges have proven exceedingly elusive. Time-dependent three-dimensional thermodynamic nonequilibrium simulations reveal the spontaneous formation of self-organized patterns of anode attachment spots in the free-burning arc, a canonical thermal plasma flow established by a constant DC current between an axi-symmetric electrodes configuration in the absence of external forcing. The number of spots, their size, and distribution within the pattern depend on the applied total current and on the resolution of the spatial discretization, whereas the main properties of the plasma flow, such as maximum temperatures, velocity, and voltage drop, depend only on the former. The sensibility of the solution to the spatial discretization stresses the computational requirements for comprehensive arc discharge simulations. The obtained anode patterns qualitatively agree with experimental observations and confirm that the spots originate at the fringes of the arc - anode attachment. The results imply that heavy-species - electron energy equilibration, in addition to thermal instability, has a dominant role in the formation of anode spots in arc discharges.

  18. JEMMRLA - Electron Model of a Muon RLA with Multi-pass Arcs

    SciTech Connect (OSTI)

    Bogacz, Slawomir Alex; Krafft, Geoffrey A.; Morozov, Vasiliy S.; Roblin, Yves R.

    2013-06-01

    We propose a demonstration experiment for a new concept of a 'dogbone' RLA with multi-pass return arcs -- JEMMRLA (Jlab Electron Model of Muon RLA). Such an RLA with linear-field multi-pass arcs was introduced for rapid acceleration of muons for the next generation of Muon Facilities. It allows for efficient use of expensive RF while the multi-pass arc design based on linear combined-function magnets exhibits a number of advantages over separate-arc or pulsed-arc designs. Here we describe a test of this concept by scaling a GeV scale muon design for electrons. Scaling muon momenta by the muon-to-electron mass ratio leads to a scheme, in which a 4.5 MeV electron beam is injected in the middle of a 3 MeV/pass linac with two double-pass return arcs and is accelerated to 18 MeV in 4.5 passes. All spatial dimensions including the orbit distortion are scaled by a factor of 7.5, which arises from scaling the 200 MHz muon RF to a readily available 1.5 GHz. The hardware requirements are not very demanding making it straightforward to implement. Such an RLA may have applications going beyond muon acceleration: in medical isotope production, radiation cancer therapy and homeland security.

  19. GALAXY HALO TRUNCATION AND GIANT ARC SURFACE BRIGHTNESS RECONSTRUCTION IN THE CLUSTER MACSJ1206.2-0847

    SciTech Connect (OSTI)

    Eichner, Thomas; Seitz, Stella; Monna, Anna [Universitaets-Sternwarte Muenchen, Scheinerstr. 1, D-81679 Muenchen (Germany); Suyu, Sherry H. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Halkola, Aleksi [Institute of Medical Engineering, University of Luebeck, Ratzeburger Allee 160 23562 Luebeck (Germany); Umetsu, Keiichi [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Zitrin, Adi [Institut fuer Theoretische Astrophysik, ZAH, Albert-Ueberle-Strasse 2, D-69120 Heidelberg (Germany); Coe, Dan; Postman, Marc; Koekemoer, Anton; Bradley, Larry [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21208 (United States); Rosati, Piero [ESO-European Southern Observatory, D-85748 Garching bei Muenchen (Germany); Grillo, Claudio; Host, Ole [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Balestra, Italo [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Zheng, Wei; Lemze, Doron [Department of Physics and Astronomy, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Broadhurst, Tom [Department of Theoretical Physics, University of the Basque Country, P.O. Box 644, E-48080 Bilbao (Spain); Moustakas, Leonidas [Jet Propulsion Laboratory, California Institute of Technology, MS 169-327, Pasadena, CA 91109 (United States); Molino, Alberto [Instituto de Astrofisica de Andalucia (CSIC), C/Camino Bajo de Huetor 24, Granada E-18008 (Spain); and others

    2013-09-10

    In this work, we analyze the mass distribution of MACSJ1206.2-0847, particularly focusing on the halo properties of its cluster members. The cluster appears relaxed in its X-ray emission, but has a significant amount of intracluster light that is not centrally concentrated, suggesting that galaxy-scale interactions are still ongoing despite the overall relaxed state. The cluster lenses 12 background galaxies into multiple images and one galaxy at z = 1.033 into a giant arc and its counterimage. The multiple image positions and the surface brightness (SFB) distribution of the arc, which is bent around several cluster members, are sensitive to the cluster galaxy halo properties. We model the cluster mass distribution with a Navarro-Frenk-White profile and the galaxy halos with two parameters for the mass normalization and the extent of a reference halo assuming scalings with their observed near-infrared light. We match the multiple image positions at an rms level of 0.''85 and can reconstruct the SFB distribution of the arc in several filters to a remarkable accuracy based on this cluster model. The length scale where the enclosed galaxy halo mass is best constrained is about 5 effective radii-a scale in between those accessible to dynamical and field strong-lensing mass estimates on the one hand and galaxy-galaxy weak-lensing results on the other hand. The velocity dispersion and halo size of a galaxy with m{sub 160W,AB} = 19.2 and M{sub B,Vega} = -20.7 are {sigma} = 150 km s{sup -1} and r Almost-Equal-To 26 {+-} 6 kpc, respectively, indicating that the halos of the cluster galaxies are tidally stripped. We also reconstruct the unlensed source, which is smaller by a factor of {approx}5.8 in area, demonstrating the increase in morphological information due to lensing. We conclude that this galaxy likely has star-forming spiral arms with a red (older) central component.

  20. Target tracking using DMLC for volumetric modulated arc therapy: A simulation study

    SciTech Connect (OSTI)

    Sun Baozhou; Rangaraj, Dharanipathy; Papiez, Lech; Oddiraju, Swetha; Yang Deshan; Li, H. Harold

    2010-12-15

    Purpose: Target tracking using dynamic multileaf collimator (DMLC) is a promising approach for intrafraction motion management in radiation therapy. The purpose of this work is to develop a DMLC tracking algorithm capable of delivering volumetric-modulated arc therapy (VMAT) to the targets that experience two-dimensional (2D) rigid motion in the beam's eye view. Methods: The problem of VMAT delivery to moving targets is formulated as a control problem with constraints. The relationships between gantry speed, gantry acceleration, MLC leaf-velocity, dose rate, and target motion are derived. An iterative search algorithm is developed to find numerical solutions for efficient delivery of a specific VMAT plan to the moving target using 2D DMLC tracking. The delivery of five VMAT lung plans is simulated. The planned and delivered fluence maps in the target-reference frame are calculated and compared. Results: The simulation demonstrates that the 2D tracking algorithm is capable of delivering the VMAT plan to a moving target fast and accurately without violating the machine constraints and the integrity of the treatment plan. The average delivery time is only 29 s longer than that of no-tracking delivery, 101 versus 72 s, respectively. The fluence maps are normalized to 200 MU and the average root-mean-square error between the desired and the delivered fluence is 2.1 MU, compared to 14.8 MU for no-tracking and 3.6 MU for one-dimensional tracking. Conclusions: A locally optimal MLC tracking algorithm for VMAT delivery is proposed, aiming at shortest delivery time while maintaining treatment plan invariant. The inconsequential increase of treatment time due to DMLC tracking is clinically desirable, which makes VMAT with DMLC tracking attractive in treating moving tumors.

  1. Accelerated molecular dynamics and equation-free methods for simulating diffusion in solids.

    SciTech Connect (OSTI)

    Deng, Jie; Zimmerman, Jonathan A.; Thompson, Aidan Patrick; Brown, William Michael; Plimpton, Steven James; Zhou, Xiao Wang; Wagner, Gregory John; Erickson, Lindsay Crowl

    2011-09-01

    Many of the most important and hardest-to-solve problems related to the synthesis, performance, and aging of materials involve diffusion through the material or along surfaces and interfaces. These diffusion processes are driven by motions at the atomic scale, but traditional atomistic simulation methods such as molecular dynamics are limited to very short timescales on the order of the atomic vibration period (less than a picosecond), while macroscale diffusion takes place over timescales many orders of magnitude larger. We have completed an LDRD project with the goal of developing and implementing new simulation tools to overcome this timescale problem. In particular, we have focused on two main classes of methods: accelerated molecular dynamics methods that seek to extend the timescale attainable in atomistic simulations, and so-called 'equation-free' methods that combine a fine scale atomistic description of a system with a slower, coarse scale description in order to project the system forward over long times.

  2. Debris Flow Mapping Through TimeDebris Flow Mapping Through Time Data Management using ArcGIS andData Management using ArcGIS and

    E-Print Network [OSTI]

    Debris Flow Mapping Through TimeDebris Flow Mapping Through Time Data Management using ArcGIS and EventsChannel Reorganizing Events ··Debris FlowsDebris Flows ··HyperHyper--concentrated Flowsconcentrated Flows #12;1.The rapid, downward mass movement of particles coarser than sand, often including boulders

  3. Gaseous and particulate emissions from a DC arc melter

    SciTech Connect (OSTI)

    Overcamp, T.J.; Speer, M.P.; Griner, S.J.; Cash, D.M. [Clemson Univ., Anderson, SC (United States)

    1997-12-31

    This paper presents the results of the gaseous and particulate emissions from eight experimental tests of a DC arc melter to treat simulated Savannah River soils contaminated with metals, surrogates for radionuclides, and organic debris. The gaseous analyses reported on the concentrations of oxygen, hydrogen, carbon monoxide, carbon dioxide, hydrogen, methane, nitric oxide, and nitrogen dioxide. The carbon dioxide concentration was high for all runs. For the runs with an air purge, the carbon monoxide concentration ranged up to 10% in the runs with the debris and 2% in the runs without debris. Hydrogen ranged up to 5% by with debris and up to 1% without debris. The methane concentration ranged up to 7,000 ppm{sub v} for the runs with debris and 2,000 ppm for the runs without debris. With a nitrogen purge, oxygen concentrations were less than 1%. The carbon dioxide concentrations ranged from 3 to 15%. Much of this carbon dioxide was probably due the carbonates added to the feed material. The carbon monoxide concentration ranged up to 20% with the debris and 7% without debris. Hydrogen was above 6% in with debris and up to 6% without debris. The methane concentration ranged up to 10,000 ppm{sub v} with debris and 4,000 ppm{sub v} without debris. The particulate concentrations exiting ranged from 32 to 145 g/m{sup 3}. From the chemical analyses, the primary elements were silicon and calcium. The CHN analyses indicated that carbon, probably as carbonates, are an additional component in the particulate matter. The estimated emissions were at a level of 3% or less for cerium, up to 7% for nickel, and 11 to 30% for cesium.

  4. Glow-to-arc transition events in H{sub 2}-Ar direct current pulsed plasma: Automated measurement of current and voltage

    SciTech Connect (OSTI)

    Mendes, Luciano A.; Rodrigues, Jhonatam C.; Mafra, Marcio

    2012-01-15

    The glow-to-arc transition phenomena (arcing) observed in plasma reactors used in materials processing was studied through the arcs characteristic current and voltage waveforms. In order to capture these arcs signals, a LABVIEW based automated instrumentation system (ARCVIEW) was developed, including the integration of an oscilloscope equipped with proper current and voltage probes. The system also allows capturing the process parameters at the arc occurrence moments, which were used to map the arcs events conditions. Experiments in H{sub 2}-Ar DC pulsed plasma returned signals data from 215 arcs events, which were analyzed through software routines. According to the results, an anti-arcing system should react in the time order of few microseconds to prevent most of the damage caused by the undesired arcing phenomena.

  5. A beginner's guide to stereo-derived DEM production and analysis using ISIS, ASP, and ArcMap

    E-Print Network [OSTI]

    Rathbun, Julie A.

    A beginner's guide to stereo-derived DEM production and analysis using ISIS, ASP, and ArcMap v. 1 ............................................................................................................................5 2. Processing the images with ISIS

  6. Jurassic arc volcanism on Crimea (Ukraine): Implications for the paleo-subduction zone configuration of the Black Sea region

    E-Print Network [OSTI]

    Utrecht, Universiteit

    Jurassic arc volcanism on Crimea (Ukraine): Implications for the paleo-subduction zone margin. Crimea (Ukraine), a peninsula in the northern Black Sea, represents the northernmost region

  7. Composition of modern sand from the Sierra Nevada, California, USA: Implications for actualistic petrofacies of continental-margin magmatic arcs

    E-Print Network [OSTI]

    Ingersoll, Raymond V.; Eastmond, Daniel J.

    2007-01-01

    variability of modern sands: Sedimentary Geology, v. 171, p.nonquartzose) lithic (L) sand(stone) composition. Designatedpredicted trend for sand(stone) composition during arc

  8. Cosmology through arc statistics I: sensitivity to $\\Omega_m$ and $\\sigma_8$

    E-Print Network [OSTI]

    Boldrin, Michele; Meneghetti, Massimo; Moscardini, Lauro; Tormen, Giuseppe; Biviano, Andrea

    2015-01-01

    The next generation of large sky photometric surveys will finally be able to use arc statistics as a cosmological probe. Here we present the first of a series of papers on this topic. In particular, we study how arc counts are sensitive to the variation of two cosmological parameters: the (total) matter density parameter, $\\Omega_m$, and the normalisation of the primordial power spectrum, expressed in terms of $\\sigma_8$. Both these parameters influence the abundances of collapsed structures and their internal structure. We compute the expected number of gravitational arcs with various length-to-width ratios in mock light cones, by varying these cosmological parameters in the ranges $0.1\\leq\\Omega_m\\leq0.5$ and $0.6\\leq\\sigma_8\\leq 1$. We find that the arc counts dependence on $\\Omega_m$ and $\\sigma_8$ is similar, but not identical, to that of the halo counts. We investigate how the precision of the constraints on the cosmological parameters based on arc counts depends on the survey area. We find that the con...

  9. Characterization of a Filtered High Current Pulsed Cathodic Vacuum Arc Plasma Source: Plasma Transport Analysis

    SciTech Connect (OSTI)

    Sangines, R.; Tarrant, R. N.; Bilek, M. M. M.; McKenzie, D. R.; Andruczyk, D.

    2008-03-19

    Studies of plasma behavior produced by a filtered high current pulsed cathodic vacuum arc system are reported. Titanium plasma is initiated from the cathode by surface flash over triggering at the centre of the cathode disk. The multiple arc spots move outwards due to their mutual repulsion and the arc current pulse is terminated as the arc spots reach the edge of the cathode disk. The plasma moves into a positively biased quarter-torus magnetic filter and is guided towards the substrate position located 150 mm beyond the filter exit. Electron density and plasma current measurements have been employed to analyze the transport of the plasma associated with different cathode currents, and its dependence on confining magnetic field and bias conditions. For a given cathode current, the optimum plasma transport to the substrate requires the right combination of the strength of the confining magnetic field and the magnetic filter positive bias. The optimum values of these two parameters were found to increase with increasing cathode current. Initially the optimum throughput of plasma increases more strongly than the arc current (roughly 1.5 times the increase in the current); however, at high cathode current regimes (2.4 kA) a significant change of the plasma behavior is seen and transport efficiency is reduced.

  10. Investigation on oblique shock wave control by arc discharge plasma in supersonic airflow

    SciTech Connect (OSTI)

    Wang Jian; Li Yinghong; Xing Fei

    2009-10-01

    Wedge oblique shock wave control by arc discharge plasma in supersonic airflow was investigated theoretically, experimentally, and numerically in this paper. Using thermal choking model, the change in oblique shock wave was deduced, which refer that the start point of shock wave shifts upstream, the shock wave angle decreases, and its intensity weakens. Then the theoretical results were validated experimentally in a Mach 2.2 wind tunnel. On the test conditions of arc discharge power of approx1 kW and arc plasma temperature of approx3000 K, schlieren photography and gas pressure measurements indicated that the start point of shock wave shifted upstream of approx4 mm, the shock wave angle decreased 8.6%, and its intensity weakened 8.8%. The deduced theoretical results match the test results qualitatively, so thermal mechanism and thermal choking model are rational to explain the problem of oblique shock wave control by arc discharge plasma. Finally, numerical simulation was developed. Based on thermal mechanism, the arc discharge plasma was simplified as a thermal source term that added to the Navier-Stokes equations. The simulation results of the change in oblique shock wave were consistent with the test results, so the thermal mechanism indeed dominates the oblique shock wave control process.

  11. The electron cyclotron resonance ion source with arc-shaped coils concept (invited)

    SciTech Connect (OSTI)

    Koivisto, H.; Tarvainen, O.; Suominen, P.; Spaedtke, P.

    2012-02-15

    The main limitation to further improve the performance of ECR ion sources is set by the magnet technology related to the multipole magnet field used for the closed minimum-B structure. The JYFL ion source group has sought different approaches to improve the strength of the minimum-B structure required for the production of highly charged ion beams. It was found out that such a configuration can be realized with arc shaped coils. The first prototype, electron cyclotron resonance ion source with arc-shaped coils (ARC-ECRIS), was constructed and tested at JYFL in 2006. It was confirmed that such an ion source can be used for the production of highly charged ion beams. Regardless of several cost-driven compromises such as extraction mirror ratio of 1.05-1.2, microwave frequency of 6.4 GHz, and beam line with limited capacity, Ar{sup 4+} beam intensity of up to 2 {mu}A was measured. Subsequent design study has shown that the ARC-ECRIS operating at the microwave frequency above 40 GHz could be constructed. This specific design would be based on NbTi-wires and it fulfills the experimental magnetic field scaling laws. In this article, the ARC-ECRIS concept and its potential applications will be described.

  12. A study of vacuum arc ion velocities using a linear set of probes

    SciTech Connect (OSTI)

    Hohenbild, Stefan; Grubel, Christoph; Yushkov, Georgy Yu.; Oks, Efim M.; Anders, Andre

    2008-07-15

    The most likely velocity of ions moving away from vacuum arc cathode spots was measured using a set of probes along the path of plasma expansion. The goal was to determine how much, if any, change of the ion drift velocity occurs in the expanded plasma. The arc discharge current was perturbed to create plasma density markers whose travel is picked up by the set of probes. It was found that the perturbation with current oscillations did not result in consistent data because ion current maxima and minima are not only determined by the plasma production but by the transients of the arc pulse and by the asymmetry of the ion velocity distribution function. Perturbation with a short current spike was more conclusive. The ion velocity was measured to be slightly reduced with increasing distance from the cathode, which can be explained by collisions of ions with the background of neutrals. The ion velocity was increased when the arc current was increased, which correlated with enhanced arc voltage and power dissipation. The ion velocity could be enhanced when the plasma was produced in a non-uniform magnetic field.

  13. Optical emission from a small scale model electric arc furnace in 250-600 nm region

    SciTech Connect (OSTI)

    Maekinen, A.; Tikkala, H.; Aksela, H.; Niskanen, J.

    2013-04-15

    Optical emission spectroscopy has been for long proposed for monitoring and studying industrial steel making processes. Whereas the radiative decay of thermal excitations is always taking place in high temperatures needed in steel production, one of the most promising environment for such studies are electric arc furnaces, creating plasma in excited electronic states that relax with intense characteristic emission in the optical regime. Unfortunately, large industrial scale electric arc furnaces also present a challenging environment for optical emission studies and application of the method is not straightforward. To study the usability of optical emission spectroscopy in real electric arc furnaces, we have developed a laboratory scale DC electric arc furnace presented in this paper. With the setup, optical emission spectra of Fe, Cr, Cr{sub 2}O{sub 3}, Ni, SiO{sub 2}, Al{sub 2}O{sub 3}, CaO, and MgO were recorded in the wavelength range 250-600 nm and the results were analyzed with the help of reference data. The work demonstrates that using characteristic optical emission, obtaining in situ chemical information from oscillating plasma of electric arc furnaces is indeed possible. In spite of complications, the method could possibly be applied to industrial scale steel making process in order to improve its efficiency.

  14. Direct-current cathodic vacuum arc system with magnetic-field mechanism for plasma stabilization

    SciTech Connect (OSTI)

    Zhang, H.-S.; Komvopoulos, K.

    2008-07-15

    Filtered cathodic vacuum arc (FCVA) deposition is characterized by plasma beam directionality, plasma energy adjustment via substrate biasing, macroparticle filtering, and independent substrate temperature control. Between the two modes of FCVA deposition, namely, direct current (dc) and pulsed arc, the dc mode yields higher deposition rates than the pulsed mode. However, maintaining the dc arc discharge is challenging because of its inherent plasma instabilities. A system generating a special configuration of magnetic field that stabilizes the dc arc discharge during film deposition is presented. This magnetic field is also part of the out-of-plane magnetic filter used to focus the plasma beam and prevent macroparticle film contamination. The efficiency of the plasma-stabilizing magnetic-field mechanism is demonstrated by the deposition of amorphous carbon (a-C) films exhibiting significantly high hardness and tetrahedral carbon hybridization (sp{sup 3}) contents higher than 70%. Such high-quality films cannot be produced by dc arc deposition without the plasma-stabilizing mechanism presented in this study.

  15. ZrN coatings deposited by high power impulse magnetron sputtering and cathodic arc techniques

    SciTech Connect (OSTI)

    Purandare, Yashodhan Ehiasarian, Arutiun; Hovsepian, Papken; Santana, Antonio

    2014-05-15

    Zirconium nitride (ZrN) coatings were deposited on 1??m finish high speed steel and 316L stainless steel test coupons. Cathodic Arc (CA) and High Power Impulse Magnetron Sputtering (HIPIMS) + Unbalanced Magnetron Sputtering (UBM) techniques were utilized to deposit coatings. CA plasmas are known to be rich in metal and gas ions of the depositing species as well as macroparticles (droplets) emitted from the arc sports. Combining HIPIMS technique with UBM in the same deposition process facilitated increased ion bombardment on the depositing species during coating growth maintaining high deposition rate. Prior to coating deposition, substrates were pretreated with Zr{sup +} rich plasma, for both arc deposited and HIPIMS deposited coatings, which led to a very high scratch adhesion value (L{sub C2}) of 100 N. Characterization results revealed the overall thickness of the coatings in the range of 2.5??m with hardness in the range of 30–40?GPa depending on the deposition technique. Cross-sectional transmission electron microscopy and tribological experiments such as dry sliding wear tests and corrosion studies have been utilized to study the effects of ion bombardment on the structure and properties of these coatings. In all the cases, HIPIMS assisted UBM deposited coating fared equal or better than the arc deposited coatings, the reasons being discussed in this paper. Thus H+U coatings provide a good alternative to arc deposited where smooth, dense coatings are required and macrodroplets cannot be tolerated.

  16. Free fall plasma-arc reactor for synthesis of carbon nanotubes in microgravity

    SciTech Connect (OSTI)

    Alford, J. M.; Mason, G. R.; Feikema, D. A.

    2006-07-15

    High temperatures inside the plasma of a carbon arc generate strong buoyancy driven convection which has an effect on the growth and morphology of the single-walled carbon nanotubes (SWNTs). To study the effect of buoyancy on the arc process, a miniature carbon arc apparatus was designed and developed to synthesize SWNTs in a microgravity environment substantially free from buoyant convective flows. An arc reactor was operated in the 2.2 and 5.18 s drop towers at the NASA Glenn Research Center. The apparatus employed a 4 mm diameter anode and was powered by a portable battery pack capable of providing in excess of 300 A at 30 V to the arc for the duration of a 5 s drop. However, the principal result is that no dramatic difference in sample yield or composition was noted between normal gravity and 2.2 and 5 s long microgravity runs. Much longer duration microgravity time is required for SWNT's growth such as the zero-G aircraft, but more likely will need to be performed on the international space station or an orbiting spacecraft.

  17. Electron Model Of A Dogbone RLA With Multi-Pass Arcs

    SciTech Connect (OSTI)

    Beard, Kevin B.; Roblin, Yves R.; Morozov, Vasiliy; Bogacz, Slawomir Alex; Krafft, Geoffrey A.

    2012-09-01

    The design of a dogbone Recirculated Linear Accelerator, RLA, with linear-field multi-pass arcs was earlier developed [1] for accelerating muons in a Neutrino Factory and a Muon Collider. It allows for efficient use of expensive RF while the multi-pass arc design based on linear combined-function magnets exhibits a number of advantages over separate-arc or pulsed-arc designs. Such an RLA may have applications going beyond muon acceleration. This paper describes a possible straightforward test of this concept by scaling a GeV scale muon design for electrons. Scaling muon momenta by the muon-to-electron mass ratio leads to a scheme, in which a 4.5 MeV electron beam is injected at the middle of a 3 MeV/pass linac with two double-pass return arcs and is accelerated to 18 MeV in 4.5 passes. All spatial dimensions including the orbit distortion are scaled by a factor of 7.5, which arises from scaling the 200 MHz muon RF to the frequency readily available at CEBAF: 1.5 GHz. The footprint of a complete RLA fits in an area of 25 by 7 m. The scheme utilizes only fixed magnetic fields including injection and extraction. The hardware requirements are not very demanding, making it straightforward to implement

  18. Linear Fixed-Field Multi-Pass Arcs for Recirculating Linear Accelerators

    SciTech Connect (OSTI)

    V.S. Morozov, S.A. Bogacz, Y.R. Roblin, K.B. Beard

    2012-06-01

    Recirculating Linear Accelerators (RLA's) provide a compact and efficient way of accelerating particle beams to medium and high energies by reusing the same linac for multiple passes. In the conventional scheme, after each pass, the different energy beams coming out of the linac are separated and directed into appropriate arcs for recirculation, with each pass requiring a separate fixed-energy arc. In this paper we present a concept of an RLA return arc based on linear combined-function magnets, in which two and potentially more consecutive passes with very different energies are transported through the same string of magnets. By adjusting the dipole and quadrupole components of the constituting linear combined-function magnets, the arc is designed to be achromatic and to have zero initial and final reference orbit offsets for all transported beam energies. We demonstrate the concept by developing a design for a droplet-shaped return arc for a dog-bone RLA capable of transporting two beam passes with momenta different by a factor of two. We present the results of tracking simulations of the two passes and lay out the path to end-to-end design and simulation of a complete dog-bone RLA.

  19. SU-E-T-226: Junction Free Craniospinal Irradiation in Linear Accelerator Using Volumetric Modulated Arc Therapy : A Novel Technique Using Dose Tapering

    SciTech Connect (OSTI)

    Sarkar, B; Roy, S; Paul, S; Munshi, A; Roy, Shilpi; Jassal, K; Ganesh, T; Mohanti, BK

    2014-06-01

    Purpose: Spatially separated fields are required for craniospinal irradiation due to field size limitation in linear accelerator. Field junction shits are conventionally done to avoid hot or cold spots. Our study was aimed to demonstrate the feasibility of junction free irradiation plan of craniospinal irradiation (CSI) for Meduloblastoma cases treated in linear accelerator using Volumetric modulated arc therapy (VMAT) technique. Methods: VMAT was planned using multiple isocenters in Monaco V 3.3.0 and delivered in Elekta Synergy linear accelerator. A full arc brain and 40° posterior arc spine fields were planned using two isocentre for short (<1.3 meter height ) and 3 isocentres for taller patients. Unrestricted jaw movement was used in superior-inferior direction. Prescribed dose to PTV was achieved by partial contribution from adjacent beams. A very low dose gradient was generated to taper the isodoses over a long length (>10 cm) at the conventional field junction. Results: In this primary study five patients were planned and three patients were delivered using this novel technique. As the dose contribution from the adjacent beams were varied (gradient) to create a complete dose distribution, therefore there is no specific junction exists in the plan. The junction were extended from 10–14 cm depending on treatment plan. Dose gradient were 9.6±2.3% per cm for brain and 7.9±1.7 % per cm for spine field respectively. Dose delivery error due to positional inaccuracy was calculated for brain and spine field for ±1mm, ±2mm, ±3mm and ±5 mm were 1%–0.8%, 2%–1.6%, 2.8%–2.4% and 4.3%–4% respectively. Conclusion: Dose tapering in junction free CSI do not require a junction shift. Therefore daily imaging for all the field is also not essential. Due to inverse planning dose to organ at risk like thyroid kidney, heart and testis can be reduced significantly. VMAT gives a quicker delivery than Step and shoot or dynamic IMRT.

  20. Study on a negative hydrogen ion source with hot cathode arc discharge

    SciTech Connect (OSTI)

    Lin, S. H. Fang, X.; University of Chinese Academy of Sciences, Beijing 100039 ; Zhang, H. J.; Qian, C.; Ma, B. H.; Wang, H.; Li, X. X.; Zhang, X. Z.; Sun, L. T.; Zhang, Z. M.; Yuan, P.; Zhao, H. W.

    2014-02-15

    A negative hydrogen (H{sup ?}) ion source with hot cathode arc discharge was designed and fabricated as a primary injector for a 10 MeV PET cyclotron at IMP. 1 mA dc H{sup ?} beam with ? {sub N,} {sub RMS} = 0.08 ??mm?mrad was extracted at 25 kV. Halbach hexapole was adopted to confine the plasma. The state of arc discharge, the parameters including filament current, arc current, gas pressure, plasma electrode bias, and the ratio of I{sub e{sup ?}}/I{sub H{sup ?}} were experimentally studied. The discussion on the result, and opinions to improve the source were given.

  1. Spectroscopic characterization and imaging of laser- and unipolar arc-induced plasmas

    SciTech Connect (OSTI)

    Aussems, Damien U. B.; Nishijima, Daisuke; Brandt, Christian; Doerner, Russell P.; Cardozo, Niek J. Lopes

    2014-08-14

    Tungsten plasmas induced by unipolar arcs were investigated using optical emission spectroscopy and imaging, and compared with laser-induced tungsten plasmas. The unipolar arcs were initiated in the linear-plasma simulator PISCES-A at UCSD under fusion relevant conditions. The electron temperature and density of the unipolar arc plasmas were in the range 0.5–0.7?eV and 0.7–2.0?×?10{sup 20?}m{sup ?3}, respectively, and increased with increasing negative bias voltage, but did not correlate with the surface temperature. In comparison, the electron temperature and density of the laser-induced plasmas were in the range 0.6–1.4?eV and 7?×?10{sup 19}–1?×?10{sup 22?}m{sup ?3}, respectively.

  2. Volumetric-modulated arc therapy (RapidArc) vs. conventional fixed-field intensity-modulated radiotherapy for {sup 18}F-FDG-PET-guided dose escalation in oropharyngeal cancer: A planning study

    SciTech Connect (OSTI)

    Teoh, May, E-mail: m.teoh@nhs.net [Department of Oncology, St. Luke's Cancer Centre, Royal Surrey County Hospital, Guildford, Surrey (United Kingdom); Beveridge, Sabeena [Department of Medical Physics, St. Luke's Cancer Centre, Royal Surrey County Hospital, Guildford, Surrey (United Kingdom); Wood, Katie; Whitaker, Stephen [Department of Oncology, St. Luke's Cancer Centre, Royal Surrey County Hospital, Guildford, Surrey (United Kingdom); Adams, Elizabeth; Rickard, Donna; Jordan, Tom; Nisbet, Andrew [Department of Medical Physics, St. Luke's Cancer Centre, Royal Surrey County Hospital, Guildford, Surrey (United Kingdom); Clark, Catharine H. [Department of Medical Physics, St. Luke's Cancer Centre, Royal Surrey County Hospital, Guildford, Surrey (United Kingdom); National Physical Laboratory, Hampton Road, Teddington, Middlesex (United Kingdom)

    2013-04-01

    Fluorine-18-fluorodeoxyglucose-positron emission tomography ({sup 18}F-FDG-PET)–guided focal dose escalation in oropharyngeal cancer may potentially improve local control. We evaluated the feasibility of this approach using volumetric-modulated arc therapy (RapidArc) and compared these plans with fixed-field intensity-modulated radiotherapy (IMRT) focal dose escalation plans. Materials and methods: An initial study of 20 patients compared RapidArc with fixed-field IMRT using standard dose prescriptions. From this cohort, 10 were included in a dose escalation planning study. Dose escalation was applied to {sup 18}F-FDG-PET–positive regions in the primary tumor at dose levels of 5% (DL1), 10% (DL2), and 15% (DL3) above standard radical dose (65 Gy in 30 fractions). Fixed-field IMRT and double-arc RapidArc plans were generated for each dataset. Dose-volume histograms were used for plan evaluation and comparison. The Paddick conformity index (CI{sub Paddick}) and monitor units (MU) for each plan were recorded and compared. Both IMRT and RapidArc produced clinically acceptable plans and achieved planning objectives for target volumes. Dose conformity was significantly better in the RapidArc plans, with lower CI{sub Paddick} scores in both primary (PTV1) and elective (PTV2) planning target volumes (largest difference in PTV1 at DL3; 0.81 ± 0.03 [RapidArc] vs. 0.77 ± 0.07 [IMRT], p = 0.04). Maximum dose constraints for spinal cord and brainstem were not exceeded in both RapidArc and IMRT plans, but mean doses were higher with RapidArc (by 2.7 ± 1 Gy for spinal cord and 1.9 ± 1 Gy for brainstem). Contralateral parotid mean dose was lower with RapidArc, which was statistically significant at DL1 (29.0 vs. 29.9 Gy, p = 0.01) and DL2 (29.3 vs. 30.3 Gy, p = 0.03). MU were reduced by 39.8–49.2% with RapidArc (largest difference at DL3, 641 ± 94 vs. 1261 ± 118, p < 0.01). {sup 18}F-FDG-PET–guided focal dose escalation in oropharyngeal cancer is feasible with RapidArc. Compared with conventional fixed-field IMRT, RapidArc can achieve better dose conformity, improve contralateral parotid sparing, and uses fewer MU.

  3. Emission and Absorption Spectroscopy of Carbon Arc Plasma during Formation of Carbon Magnetic Encapsulates

    SciTech Connect (OSTI)

    Lange, H.; Labedz, O.; Huczko, A.; Bystrzejewski, M.

    2011-11-29

    Plasma diagnostics of carbon arc discharge under conditions of carbon magnetic encapsulates formation was performed by emission and absorption spectroscopy. Content of C{sub 2} and Fe species, rotational temperatures of excited (d {sup 3} product {sub g}) and non-excited (a {sup 3} product {sub u}) states, and excitation temperatures of a {sup 5}F and a {sup 3}F levels relatively to the a {sup 5}D level of Fe atoms were determined. The results pointed to a non-equilibrium state of carbon arc plasma under prevailing discharge conditions.

  4. Super-radiance in the sodium resonance lines from sodium iodide arc lamps

    SciTech Connect (OSTI)

    Karabourniotis, D.; Drakakis, E.

    2010-08-09

    Super-radiance observed within the centers of the sodium resonance D lines emitted by arc lamps containing sodium iodide as additive in a high-pressure mercury plasma environment was studied by high-resolution emission spectroscopy. The spectral radiance of these self-reversed lines including super-radiance was simulated by considering a local enhancement of the source function due to the presence of an additional source of radiation near the arc wall. Causes of this hitherto unrecognized source of radiation are given.

  5. Optical Analysis Of The Vacuum Arc Plasma Generated In Cup-Shape Contacts

    SciTech Connect (OSTI)

    Pavelescu, G.; Gherendi, F.; Pavelescu, D.; Dumitrescu, G.; Anghelita, P.

    2007-04-23

    In this paper are presented the results of the optical analysis on the rotating arc plasma, generated in the vacuum low voltage circuit breaker with cup-shaped contacts. An adequate experimental setup was used for single shot time and spatial resolved spectroscopy in order to analyze the evolution of the vacuum arc plasma. Different current interruption situations are correlated with plasma spectral diagnosis. The study is aimed to contribute to a better understanding of the complex phenomena that take place in the interruption process of high currents that appears in the short-circuit regime of electrical networks.

  6. IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. PS-8, NO. 4, DECEMBER 1980 Behavior of a High Current Vacuum Arc Between

    E-Print Network [OSTI]

    Jerby, Eli

    IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. PS-8, NO. 4, DECEMBER 1980 Behavior of a High Current Vacuum Arc Between Hollow Cylindrical Electrodes in a Radial Magnetic Field RAYMOND L. BOXMAN, SENIOR on the behavior 0 54mm of a high current vacuum arc on cylindrical electrodes in a radial mag- 15mm netic field

  7. Advanced plasma flow simulations of cathodic-arc and ferroelectric plasma sources for neutralized drift compression experiments

    E-Print Network [OSTI]

    Gilson, Erik

    Advanced plasma flow simulations of cathodic-arc and ferroelectric plasma sources for neutralized cathodic-arc plasma source show the coupling efficiency of the plasma flow from the source to the drift drift compression experiments Adam B. Sefkow, Ronald C. Davidson, and Erik P. Gilson Plasma Physics

  8. Accelerated Life Testing of PV Arc-Fault Detectors Jay Johnson, Michael Neilsen, Paul Vianco, N. Rob Sorensen,

    E-Print Network [OSTI]

    interrupters (AFCIs) to be incorporated into photovoltaic (PV) systems to prevent fires. Some manufacturers-fault prevention devices. Index Terms -- photovoltaic systems, arc-fault detectors, accelerated life testing on the photovoltaic (PV) system. While there has been extensive work to create functionally robust arc-fault detectors

  9. Instability of a Vacuum Arc Centrifuge M. J. Hole, R. S. Dallaqua, S. W. Simpson* and E. Del Bosco.

    E-Print Network [OSTI]

    Instability of a Vacuum Arc Centrifuge M. J. Hole, R. S. Dallaqua, S. W. Simpson* and E. Del Bosco, SP, Brazil Abstract. Ever since conception of the Vacuum Arc Centrifuge (VAC) in 1980, periodic predictions and compare with detailed experiments conducted on the PCEN centrifuge at the Brazilian National

  10. Linking ArcView 3.0TM and XGobi: Insight Behind the Front End

    E-Print Network [OSTI]

    Symanzik, Jürgen

    of the implementation of a bidirectional link between the Geographic Information System GIS ArcView 3.0TM; Geographic information system; Imple- mentation issues; Spatial cumulative distribution function; Spatial statistics; Spatially lagged scatterplot; Variogram cloud plot. 1 Introduction Geographic Information Systems

  11. CHANGES IN SOLIDIFICATION MODE, AND THE MEASUREMENT OF COOLING RATES FOLLOWING SOLIDIFICATION DURING ARC WELDING

    E-Print Network [OSTI]

    Cambridge, University of

    SOLIDIFICATION DURING ARC WELDING 2.1 INTRODUCTION The solidification process in a weld pool has been shown to have a considerable in- fluence upon the properties of the resultant weld. It influences elements, and hence the homogeneity of the weld. Previous work on the cooling behaviour of welds (Garland

  12. Improved Microstructure and Properties of 6061 Aluminum Alloy Weldments Using a Double-Sided Arc Welding

    E-Print Network [OSTI]

    Zhang, YuMing

    Welding Process Y.M. ZHANG, C. PAN, and A.T. MALE Due to its popularity and high crack sensitivity, 6061 aluminum alloy was selected as a test material for the newly developed double-sided arc welding (DSAW systematically. The percentage of fine equiaxed grains in the fully penetrated welds is greatly increased

  13. Computational Modeling of Microstructural-Evolution in AISI 1005 Steel During Gas Metal Arc Butt Welding

    E-Print Network [OSTI]

    Grujicic, Mica

    Welding M. Grujicic, S. Ramaswami, J.S. Snipes, R. Yavari, A. Arakere, C.-F. Yen, and B.A. Cheeseman-mechanical finite-element procedure is developed to model conventional gas metal arc welding (GMAW) butt of the workpiece and the weld temperature- dependent and by allowing the potential work of plastic deformation

  14. GIS Fundamentals: Introduction to GIS Lesson 3, Digitizing Lesson 3: Digitizing in ArcMap

    E-Print Network [OSTI]

    Butler, Christopher J.

    GIS Fundamentals: Introduction to GIS Lesson 3, Digitizing Lesson 3: Digitizing in ArcMap What You Chapter 4 in the GIS Fundamentals textbook before starting this lab, as the chapter covers the basics on how the photo was taken (flying height, terrain, camera tilt, and other factors). GIS data

  15. Arc Fault Risk Assessment and Degradation Model Development for Photovoltaic Connectors

    E-Print Network [OSTI]

    Arc Fault Risk Assessment and Degradation Model Development for Photovoltaic Connectors Benjamin B of photovoltaic installations information necessary to develop a data-driven plan for BOS connector maintenance, reliability I. INTRODUCTION As the reliability of traditional photovoltaic (PV) modules becomes better

  16. www.esri.com ArcUser Fall 2010 7 Continued on page 8

    E-Print Network [OSTI]

    Wright, Dawn Jeannine

    Answering Real-World An antiaircraft gun point feature has been symbolized as two threat dome layers by the visibility volume for the antiaircraft gun. #12;8 ArcUser Fall 2010 www.esri.com Some geographic questions.Thisisaninherently3Dprob- lem, because the ranges calculated for weapons are often based on direct 3D distances

  17. UWB radar technique for arc detection in coaxial cables and waveguides

    SciTech Connect (OSTI)

    Maggiora, R.; Salvador, S.

    2009-11-26

    As spread spectrum technology has revolutionized the communications industry, Ultra Wide Band (UWB) technology is dramatically improving radar performances. These advanced signal processing techniques have been adapted to coaxial cables and waveguides to provide new features and enhanced performance on arc detection. UWB signals constituted by a sequence of chips (properly chosen to reduce side lobes and to improve detection accuracy) are transmitted along the transmission lines at a specified Pulse Repetition Frequency (PRF) and their echoes are received by means of directional couplers. The core of the receiver is an ultra high-speed correlator implemented in a Digital Signal Processor (DSP). When a target (arc) is detected, its position and its 'radar cross section' are calculated to be able to provide the arc position along the transmission line and to be able to classify the type of detected arc. The 'background scattering' is routinely extracted from the received signal at any pulse. This permits to be resilient to the background structure of transmission lines (bends, junctions, windows, etc.). Thanks to the localization feature, segmentation is also possible for creating sensed and non-sensed zones (for example, to be insensitive to antenna load variations)

  18. A Summary of Recent Experimental Research on Ion Energy and Charge States of Pulsed Vacuum Arcs

    SciTech Connect (OSTI)

    Oks, Efim M.; Yushkov, Georgy Yu.; Anders, Andre

    2008-06-16

    The paper reviews the results of vacuum arc experimental investigations made collaboratively by research groups from Berkeley and Tomsk over the last two years, i.e. since the last ISDEIV in 2006. Vacuum arc plasma of various metals was produced in pulses of a few hundred microseconds duration, and the research focussed on three topics: (i) the energy distribution functions for different ion charge states, (ii) the temporal development of the ion charge state distribution, and (iii) the evolution of the mean directed ion velocities during plasma expansion. A combined quadruple mass-to-charge and energy ana-lyzer (EQP by HIDEN Ltd) and a time-of-flight spectrometer were employed. Cross-checking data by those complimen-tary techniques helped to avoid possible pitfalls in interpre-tation. It was found that the ion energy distribution func-tions in the plasma were independent of the ion charge state, which implies that the energy distribution on a substrate are not equal to due to acceleration in the substrate's sheath. In pulsed arc mode, the individual ion charge states fractions showed changes leading to a decrease of the mean charge state toward a steady-state value. This decrease can be re-duced by lower arc current, higher pulse repetition rate and reduced length of the discharge gap. It was also found that the directed ion velocity slightly decreased as the plasma expanded into vacuum.

  19. High current multicharged metal ion source using high power gyrotron heating of vacuum arc plasma

    SciTech Connect (OSTI)

    Vodopyanov, A. V.; Golubev, S. V.; Khizhnyak, V. I.; Mansfeld, D. A.; Nikolaev, A. G.; Oks, E. M.; Savkin, K. P.; Vizir, A. V.; Yushkov, G. Yu.

    2008-02-15

    A high current, multi charged, metal ion source using electron heating of vacuum arc plasma by high power gyrotron radiation has been developed. The plasma is confined in a simple mirror trap with peak magnetic field in the plug up to 2.5 T, mirror ratio of 3-5, and length variable from 15 to 20 cm. Plasma formed by a cathodic vacuum arc is injected into the trap either (i) axially using a compact vacuum arc plasma gun located on axis outside the mirror trap region or (ii) radially using four plasma guns surrounding the trap at midplane. Microwave heating of the mirror-confined, vacuum arc plasma is accomplished by gyrotron microwave radiation of frequency 75 GHz, power up to 200 kW, and pulse duration up to 150 {mu}s, leading to additional stripping of metal ions by electron impact. Pulsed beams of platinum ions with charge state up to 10+, a mean charge state over 6+, and total (all charge states) beam current of a few hundred milliamperes have been formed.

  20. Effects of induced flow on the depths of active back-arc basins 

    E-Print Network [OSTI]

    Tomlins, Robynn Lee

    1993-01-01

    The depth of active back-arc basins, younger than 10 Ma is correlated to the angle of subduction, in that the deepest basins are associated with steep angles of subduction, and the shallowest to small angles of subduction. A two-dimensional comer...

  1. Submarine venting of liquid carbon dioxide on a Mariana Arc volcano

    E-Print Network [OSTI]

    Chadwick, Bill

    Submarine venting of liquid carbon dioxide on a Mariana Arc volcano John Lupton NOAA/Pacific Marine, Washington 98115-6349, USA Cornel de Ronde Institute of Geological and Nuclear Sciences, 30 Gracefield Road, California, 92065, USA [1] Although CO2 is generally the most abundant dissolved gas found in submarine

  2. A static voltage-current characteristic for the low current DC arc 

    E-Print Network [OSTI]

    Moores, Gregory Lee

    1998-01-01

    on bare I8AWG solid copper electrodes in geometries simulating Sow current arcs, between wires of a typical cable bundle (1-6 amps and 12-125mils long). Using multiple linear regression the data was fitted to 18 different models, new or proposed...

  3. The Magnetite Crisis in the Evolution of Arc-related Magmas and the Initial

    E-Print Network [OSTI]

    Lee, Cin-Ty Aeolus

    and back-arc magma series is their association with ores of the rare, but economically important metals Au of these metals is not straightforward. For Au, one of the rarest metals on Earth, with a primitive mantle RESEARCH SCHOOL OF EARTH SCIENCES, AUSTRALIAN NATIONAL UNIVERSITY, CANBERRA, ACT 0200, AUSTRALIA RECEIVED

  4. Discovery of Red Selected Arcs at z=4.04 behind Abell 2390

    E-Print Network [OSTI]

    Brenda Frye; Tom Broadhurst

    1997-12-08

    We describe the properties of a system of red arcs discovered at z=4.04 around the cluster A2390 ($z=0.23$). These arcs are images of a single galaxy, where the lensing is compounded by an elliptical cluster member lying close to the critical curve of the cluster. The combined magnification is estimated to be $\\sim 20$, using HST images, depending the gradient of the model potentials, implying an unlensed magnitude for the source of $I_{AB}=25.5$. Keck spectroscopy reveals a continuum well fitted by B-stars and attenuated by the Lyman-series forest with an opacity consistent with z$\\sim$4 QSO spectra, making the arcs relatively red. Damped Ly$\\alpha$ absorption is observed at the source redshift with a relatively high column, n$_{HI}=3\\times 10^{21}$. Curiously, Ly$\\alpha$ emission is spatially separated ($\\sim 0.5$kpc) from the bright stellar continuum and lies $\\sim$ 300Km/s redward of interstellar absorption lines at z=4.04. Similar redwardl of young galaxies. Finally, we briefly comment on the notorious ``straight arc'' in A2390, which is resolved into two unrelated galaxies at z=0.913 and z=1.033.

  5. (Smart) Look-Ahead Arc Consistency and the Pursuit of CSP Tractability

    E-Print Network [OSTI]

    Dalmau, Victor

    (Smart) Look-Ahead Arc Consistency and the Pursuit of CSP Tractability Hubie Chen 1 and V#19. The constraint satisfaction problem (CSP) can be formu- lated as the problem of deciding, given a pair (A; B) of relational struc- tures, whether or not there is a homomorphism from A to B. Although the CSP is in general

  6. U^Pb geochronology of Seychelles granitoids: a Neoproterozoic continental arc fragment

    E-Print Network [OSTI]

    Torsvik, Trond Helge

    U^Pb geochronology of Seychelles granitoids: a Neoproterozoic continental arc fragment R.D. Tucker reserved. Keywords: U/Pb; geochronology; Neoproterozoic; magmatism; Rodinia; reconstruction; Seychelles 1 of these rocks was ¢rst established [2^4]. Since then, numerous geochronological studies of Sey- chelles

  7. Archived as condmat/yymmnnn and mp arc yynnn Preprint CPTXXX98 Rigidity of interfaces

    E-Print Network [OSTI]

    Archived as cond­mat/yymmnnn and mp arc yy­nnn Preprint CPT­XXX­98 Rigidity of interfaces) Dedicated to the memory of Roland Dobrushin Abstract We analyze the thermodynamic properties of interfaces that the 100 interface in this model, at half­filling, is rigid, as in the three­dimensional Ising model

  8. 10/3/08 10:11 AMBiden energizes crowd at ARC Page 1 of 3http://columbiatribune.com/2008/sep/20080909news004.asp

    E-Print Network [OSTI]

    Glaser, Rainer

    10/3/08 10:11 AMBiden energizes crowd at ARC Page 1 of 3http://columbiatribune.com/2008/sep Sports Forum Biden energizes crowd at ARC VP nominee criticizes McCain-Palin. By JASON ROSENBAUM used last week's #12;10/3/08 10:11 AMBiden energizes crowd at ARC Page 2 of 3http

  9. An interferometric and spectroscopic argon arc plasma diagnostic This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-Print Network [OSTI]

    An interferometric and spectroscopic argon arc plasma diagnostic This article has been downloaded An interferometric and spectroscopic argon arc plasma diagnostic K MusioltS, A Czernichowskit, J ChapelleS and C de diagnostics of an arc plasma, when the halfwidth of the Balmer H, line is measured, there is a certain amount

  10. Structurally Integrated Coatings for Wear and Corrosion (SICWC): Arc Lamp, InfraRed (IR) Thermal Processing

    SciTech Connect (OSTI)

    Mackiewicz-Ludtka, G.; Sebright, J.

    2007-12-15

    The primary goal of this Cooperative Research and Development Agreement (CRADA) betwe1311 UT-Battelle (Contractor) and Caterpillar Inc. (Participant) was to develop the plasma arc lamp (PAL), infrared (IR) thermal processing technology 1.) to enhance surface coating performance by improving the interfacial bond strength between selected coatings and substrates; and 2.) to extend this technology base for transitioning of the arc lamp processing to the industrial Participant. Completion of the following three key technical tasks (described below) was necessary in order to accomplish this goal. First, thermophysical property data sets were successfully determined for composite coatings applied to 1010 steel substrates, with a more limited data set successfully measured for free-standing coatings. These data are necessary for the computer modeling simulations and parametric studies to; A.) simulate PAL IR processing, facilitating the development of the initial processing parameters; and B.) help develop a better understanding of the basic PAL IR fusing process fundamentals, including predicting the influence of melt pool stirring and heat tnmsfar characteristics introduced during plasma arc lamp infrared (IR) processing; Second, a methodology and a set of procedures were successfully developed and the plasma arc lamp (PAL) power profiles were successfully mapped as a function of PAL power level for the ORNL PAL. The latter data also are necessary input for the computer model to accurately simulate PAL processing during process modeling simulations, and to facilitate a better understand of the fusing process fundamentals. Third, several computer modeling codes have been evaluated as to their capabilities and accuracy in being able to capture and simulate convective mixing that may occur during PAL thermal processing. The results from these evaluation efforts are summarized in this report. The intention of this project was to extend the technology base and provide for transitioning of the arc lamp processing to the industrial Participant.

  11. SCALED ELECTRON MODEL OF A DOGBONE MUON RLA WITH MULTI-PASS ARCS

    SciTech Connect (OSTI)

    Kevin Beard, Rolland Johnson, Vasiliy Morozov, Yves Roblin, Andrew Hutton, Geoffrey Krafft, Slawomir Bogacz

    2012-07-01

    The design of a dogbone RLA with linear-field multi-pass arcs was earlier developed for accelerating muons in a Neutrino Factory and a Muon Collider. It allows for efficient use of expensive RF while the multi-pass arc design based on linear combined-function magnets exhibits a number of advantages over separate-arc or pulsed-arc designs. Such an RLA may have applications going beyond muon acceleration. This paper describes a possible straightforward test of this concept by scaling a GeV scale muon design for electrons. Scaling muon momenta by the muon-to-electron mass ratio leads to a scheme, in which a 4.5 MeV electron beam is injected at the middle of a 3 MeV/pass linac with two double-pass return arcs and is accelerated to 18 MeV in 4.5 passes. All spatial dimensions including the orbit distortion are scaled by a factor of 7.5, which arises from scaling the 200 MHz muon RF to a readily available at CEBAF 1.5 GHz. The footprint of a complete RLA fits in an area of 25 by 7 m. The scheme utilizes only fixed magnetic fields including injection and extraction. The hardware requirements are not very demanding, making it straightforward to implement. In this report, we have shown first of all that measuring the energy spectrum of the fast neutrons in the liquid scintillators allows one to distinguish the two chemical forms of plutonium. In addition, combining this information with the Feynman 2-neutron and 3-neutron correlations allows one to extract the {alpha}-ratio without explicitly knowing the multiplication. Given the {alpha}-ratio one can then extract the multiplication as well as the {sup 239}Pu and {sup 240}Pu masses directly from the moment equations.

  12. How Common are Noise Sources on the Crash Arc of Malaysian Flight 370

    SciTech Connect (OSTI)

    Fenimore, Edward E.; Kunkle, Thomas David; Stead, Richard J.

    2014-10-21

    Malaysian Flight 370 disappeared nearly without a trace. Besides some communication handshakes to the INMASAT satellite, the Comprehensive Test Ban Treaty monitoring system could have heard the aircraft crash into the southern Indian Ocean. One noise event from Cape Leeuwin has been suggested by Stead as the crash and occurs within the crash location suggested by Kunkle at el. We analyze the hydrophone data from Cape Leeuwin to understand how common such noise events are on the arc of possible locations where Malaysian Flight 370 might have crashed. Few other noise sources were found on the arc. The noise event found by Stead is the strongest. No noise events are seen within the Australian Transportation Safety Board (ATSB) new search location until the 10th strongest event, an event which is very close to the noise level.

  13. A review comparing cathodic arcs and high power impulse magnetron sputtering (HiPIMS)

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Anders, Andre

    2014-10-01

    High power impulse magnetron sputtering (HiPIMS) has been in the center of attention over the last years as it is an emerging physical vapor deposition (PVD) technology that combines advantages of magnetron sputtering with various forms of energetic deposition of films such as ion plating and cathodic arc plasma deposition. It should not come at a surprise that many extension and variations of HiPIMS make use, intentionally or unintentionally, of previously discovered approaches to film processing such as substrate surface preparation by metal ion sputtering and phased biasing for film texture and stress control. Therefore, in this review, an overview is given on some historical developments and features of cathodic arc and HiPIMS plasmas, showing commonalities and differences. To limit the scope, emphasis is put on plasma properties, as opposed to surveying the vast literature on specific film materials and their properties.

  14. Use of vacuum arc plasma guns for a metal puff Z-pinch system

    SciTech Connect (OSTI)

    Rousskikh, A. G.; Zhigalin, A. S.; Oreshkin, V. I.; Chaikovsky, S. A.; Labetskaya, N. A.; Baksht, R. B.

    2011-09-15

    The performance of a metal puff Z-pinch system has been studied experimentally. In this type of system, the initial cylindrical shell 4 cm in diameter was produced by ten plasma guns. Each gun initiates a vacuum arc operating between magnesium electrodes. The net current of the guns was 80 kA. The arc-produced plasma shell was compressed by using a 450-kA, 450-ns driver, and as a result, a plasma column 0.3 cm in diameter was formed. The electron temperature of the plasma reached 400 eV at an average ion concentration of 1.85 {center_dot} 10{sup 18} cm{sup -3}. The power of the Mg K-line radiation emitted by the plasma for 15-30 ns was 300 MW/cm.

  15. Ion Species and Charge States of Vacuum Arc Plasma with Gas Feed and Longitudinal Magnetic Field

    SciTech Connect (OSTI)

    Oks, Efim; Anders, Andre

    2010-06-23

    The evolution of copper ion species and charge state distributions is measured for a long vacuum arc discharge plasma operated in the presence of a longitudinal magnetic field of several 10 mT and working gas (Ar). It was found that changing the cathode-anode distance within 20 cm as well as increasing the gas pressure did not affect the arc burning voltage and power dissipation by much. In contrast, burning voltage and power dissipation were greatly increased as the magnetic field was increased. The longer the discharge gap the greater was the fraction of gaseous ions and the lower the fraction of metal ions, while the mean ion charge state was reduced. It is argued that the results are affected by charge exchange collisions and electron impact ionization.

  16. Graphene layer growth on silicon substrates with nickel film by pulse arc plasma deposition

    SciTech Connect (OSTI)

    Fujita, K.; Banno, K.; Aryal, H. R.; Egawa, T.

    2012-10-15

    Carbon layer has been grown on a Ni/SiO{sub 2}/Si(111) substrate under high vacuum pressure by pulse arc plasma deposition. From the results of Raman spectroscopy for the sample, it is found that graphene was formed by ex-situ annealing of sample grown at room temperature. Furthermore, for the sample grown at high temperature, graphene formation was shown and optimum temperature was around 1000 Degree-Sign C. Transmission electron microscopy observation of the sample suggests that the graphene was grown from step site caused by grain of Ni film. The results show that the pulse arc plasma technique has the possibility for acquiring homogenous graphene layer with controlled layer thickness.

  17. Measurements of the Ion Species of Cathodic Arc Plasma in an Axial Magnetic Field

    SciTech Connect (OSTI)

    Oks, Efim; Anders, Andre

    2010-10-19

    Metal and gas ion species and their charge state distributions were measured for pulsed copper cathodic arcs in argon background gas in the presence of an axial magnetic field. It was found that changing the cathode position relative to anode and ion extraction system as well as increasing the gas pressure did not much affect the arc burning voltage and the related power dissipation. However, the burning voltage and power dissipation greatly increased as the magnetic field strength was increased. The fraction of metal ions and the mean ion charge state were reduced as the discharge length was increased. The observations can be explained by the combination of charge exchange collisions and electron impact ionization. They confirm that previously published data on characteristic material-dependent charge state distributions (e.g., Anders and Yushkov, J. Appl. Phys., Vol. 91, pp. 4824-4832, 2002) are not universal but valid for high vacuum conditions and the specifics of the applied magnetic fields.

  18. Schlieren technique applied to the arc temperature measurement in a high energy density cutting torch

    SciTech Connect (OSTI)

    Prevosto, L.; Mancinelli, B.; Artana, G.; Kelly, H.

    2010-01-15

    Plasma temperature and radial density profiles of the plasma species in a high energy density cutting arc have been obtained by using a quantitative schlieren technique. A Z-type two-mirror schlieren system was used in this research. Due to its great sensibility such technique allows measuring plasma composition and temperature from the arc axis to the surrounding medium by processing the gray-level contrast values of digital schlieren images recorded at the observation plane for a given position of a transverse knife located at the exit focal plane of the system. The technique has provided a good visualization of the plasma flow emerging from the nozzle and its interactions with the surrounding medium and the anode. The obtained temperature values are in good agreement with those values previously obtained by the authors on the same torch using Langmuir probes.

  19. Plasma chemistry fluctuations in a reactive arc plasma in the presence of magnetic fields

    SciTech Connect (OSTI)

    Rosen, J.; Anders, A.; Schneider, J.M.

    2002-01-13

    The effect of a magnetic field on the plasma chemistry and pulse-to-pulse fluctuations of cathodic arc ion charge state distributions in a reactive environment were investigated. The plasma composition was measured by time-of-flight charge-to-mass spectrometry. The fluctuation of the concentrations of Al+, Al2+ and Al3+ was found to increase with an increasing magnetic field strength. We suggest that this is caused by magnetic field dependent fluctuations of the energy input into cathode spots as seen through fluctuations of the cathode potential. These results are qualitatively consistent with the model of partial local Saha equilibrium and are of fundamental importance for the evolution of the structure of films deposited by reactive cathodic arc deposition.

  20. Tomographic interferometry of a filtered high-current vacuum arc plasma

    SciTech Connect (OSTI)

    Warr, George B.; Tarrant, Richard N.; Bilek, Marcela M. M.; McKenzie, David R.; Harris, Jeffrey H.; Howard, John; Blackwell, Boyd D.

    2007-04-01

    Tomography of a plasma enables the distribution of electron density to be visualized. We report on the design of two tomographic interferometer systems used to measure plasma electron density distributions in a high-current pulsed cathodic vacuum arc. The method is shown to be capable of microsecond time resolution. The spatial resolution of the quasioptical interferometer operating at 2 mm wavelength is 20 mm and the spatial resolution of the waveguide-based interferometer operating at 8 mm wavelength is 50 mm. In both cases the resolution achieved depends on the launching and receiving geometries. We developed criteria for assessing the tomogram for artifacts arising from limited sampling. First results of the spatial and temporal history of plasma in a high-current vacuum arc guided by a curved magnetic filter are presented and indicate poloidal field fluctuations reminiscent of magnetohydrodynamic instabilities in pinches. The applicability of the tomographic interferometry method to optimize plasma transport through the filter is also demonstrated.

  1. Mechanism of surface modification in the plasma-surface interaction in electrical arcs

    E-Print Network [OSTI]

    Timko, H; Nordlund, K; Costelle, L; Matyash, K; Schneider, R; Toerklep, A; Arnau-Izquierdo, G; Descoeudres, A; Calatroni, S; Taborelli, M; Wuensch, W

    2010-01-01

    Electrical sparks and arcs are plasma discharges that carry large currents and can strongly modify surfaces. This damage usually comes in the form of micrometer-sized craters and frozen-in liquid on the surface. Using a combination of experiments, plasma and atomistic simulation tools, we now show that the observed formation of deep craters and liquidlike features during sparking in vacuum is explained by the impacts of energetic ions, accelerated under the given conditions in the plasma sheath to kiloelectron volt energies, on surfaces. The flux in arcs is so high that in combination with kiloelectron volt energies it produces multiple overlapping heat spikes, which can lead to cratering even in materials such as Cu, where a single heat spike normally does not.

  2. Mechanism of surface modification in the plasma surface interaction in electrical arcs

    E-Print Network [OSTI]

    Timko, Helga; Djurabekova, Flyura; Nordlund, Kai; Matyash, Konstantin; Schneider, Ralf; Toerklep, Anders; Arnau-Izquierdo, Gonzalo; Descoeudres, Antoine; Calatroni, Sergio; Taborelli, Mauro; Wuensch, Walter

    2010-01-01

    Electrical sparks and arcs are plasma discharges that carry large currents and can strongly modify surfaces. This damage usually comes in the form of micrometer-sized craters and frozen-in liquid on the surface. Using a combination of experiments, plasma and atomistic simulation tools, we now show that the observed formation of deep craters and liquidlike features during sparking in vacuum is explained by the impacts of energetic ions, accelerated under the given conditions in the plasma sheath to kiloelectron volt energies, on surfaces. The flux in arcs is so high that in combination with kiloelectron volt energies it produces multiple overlapping heat spikes, which can lead to cratering even in materials such as Cu, where a single heat spike normally does not.

  3. Transparent and conductive indium doped cadmium oxide thin films prepared by pulsed filtered cathodic arc deposition

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhu, Yuankun; Mendelsberg, Rueben J.; Zhu, Jiaqi; Han, Jiecai; Anders, André

    2012-11-26

    Indium doped cadmium oxide (CdO:In) films with different In concentrations were prepared on low-cost glass substrates by pulsed filtered cathodic arc deposition (PFCAD). In this study, it is shown that polycrystalline CdO:In films with smooth surface and dense structure are obtained. In-doping introduces extra electrons leading to remarkable improvements of electron mobility and conductivity, as well as improvement in the optical transmittance due to the Burstein Moss effect. CdO:In films on glass substrates with thickness near 230 nm show low resistivity of 7.23 x 10-5 ?cm, high electron mobility of 142 cm2/Vs, and mean transmittance over 80% from 500-1250 nmmore »(including the glass substrate). These high quality pulsed arc-grown CdO:In films are potentially suitable for high efficiency multi-junction solar cells that harvest a broad range of the solar spectrum.« less

  4. Transparent and conductive indium doped cadmium oxide thin films prepared by pulsed filtered cathodic arc deposition

    SciTech Connect (OSTI)

    Zhu, Yuankun; Mendelsberg, Rueben J.; Zhu, Jiaqi; Han, Jiecai; Anders, André

    2012-11-26

    Indium doped cadmium oxide (CdO:In) films with different In concentrations were prepared on low-cost glass substrates by pulsed filtered cathodic arc deposition (PFCAD). In this study, it is shown that polycrystalline CdO:In films with smooth surface and dense structure are obtained. In-doping introduces extra electrons leading to remarkable improvements of electron mobility and conductivity, as well as improvement in the optical transmittance due to the Burstein Moss effect. CdO:In films on glass substrates with thickness near 230 nm show low resistivity of 7.23 x 10-5 ?cm, high electron mobility of 142 cm2/Vs, and mean transmittance over 80% from 500-1250 nm (including the glass substrate). These high quality pulsed arc-grown CdO:In films are potentially suitable for high efficiency multi-junction solar cells that harvest a broad range of the solar spectrum.

  5. A review comparing cathodic arcs and high power impulse magnetron sputtering (HiPIMS)

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Anders, André

    2014-09-02

    In this study, high power impulse magnetron sputtering (HiPIMS) has been in the center of attention over the last years as it is an emerging physical vapor deposition (PVD) technology that combines advantages of magnetron sputtering with various forms of energetic deposition of films such as ion plating and cathodic arc plasma deposition. It should not come at a surprise that many extension and variations of HiPIMS make use, intentionally or unintentionally, of previously discovered approaches to film processing such as substrate surface preparation by metal ion sputtering and phased biasing for film texture and stress control. Therefore, in thismore »review, an overview is given on some historical developments and features of cathodic arc and HiPIMS plasmas, showing commonalities and differences. To limit the scope, emphasis is put on plasma properties, as opposed to surveying the vast literature on specific film materials and their properties.« less

  6. On the long-term correlations and multifractal properties of electric arc furnace time series

    E-Print Network [OSTI]

    Livi, Lorenzo; Rizzi, Antonello; Sadeghian, Alireza

    2015-01-01

    In this paper, we study long-term correlations and multifractal properties elaborated from time series of three-phase current signals coming from an industrial electric arc furnace plant. Implicit sinusoidal trends are suitably detected in the scaling of the fluctuation function of such time series. Time series are then initially filtered via a Fourier based analysis, removing hence such strong periodicities. In the filtered time series we detected long-term, positive correlations. The presence of persistent correlations is in agreement with the typical V--I characteristic (hysteresis) of the electric arc furnace, justifying thus the memory effects found in the current time series. The multifractal signature is strong enough in the filtered time series to be effectively classified as multifractal.

  7. Transparent and conductive indium doped cadmium oxide thin films prepared by pulsed filtered cathodic arc deposition

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhu, Yuankun [Harbin Institute of Technology (China). Center for Composite Materials and Structures; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Plasma Applications Group; Mendelsberg, Rueben J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Plasma Applications Group and Molecular Foundry; Zhu, Jiaqi [Harbin Institute of Technology (China). Center for Composite Materials and Structures; Han, Jiecai [Harbin Institute of Technology (China). Center for Composite Materials and Structures; Anders, Andre [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Plasma Applications Group

    2013-01-01

    Indium doped cadmium oxide (CdO:In) films with different In concentrations were prepared on low-cost glass substrates by pulsed filtered cathodic arc deposition (PFCAD). It is shown that polycrystalline CdO:In films with smooth surface and dense structure are obtained. In-doping introduces extra electrons leading to remarkable improvements of electron mobility and conductivity, as well as improvement in the optical transmittance due to the Burstein Moss effect. CdO:In films on glass substrates with thickness near 230 nm show low resistivity of 7.23 10-5 cm, high electron mobility of 142 cm2/Vs, and mean transmittance over 80percent from 500-1250 nm (including the glass substrate). These high quality pulsed arc-grown CdO:In films are potentially suitable for high efficiency multi-junction solar cells that harvest a broad range of the solar spectrum.

  8. 518 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 33, NO. 2, APRIL 2005 Plasma Dynamics During Breakdown in

    E-Print Network [OSTI]

    Kushner, Mark

    , lamp, modeling, plasma. METAL halide arc lamps are widely used sources of in- door and large area518 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 33, NO. 2, APRIL 2005 Plasma Dynamics During plasma hydrodynamics model was used to investigate breakdown in metal halide lamp. Images depicting

  9. Puzzling differences in bismuth and lead plasmas: evidence for the significant role of neutrals in cathodic vacuum arcs

    E-Print Network [OSTI]

    Anders, Andre; Yushkov, Georgy Yu.

    2007-01-01

    vacuum arcs for (a) lead plasma, (b) bismuth plasma. Arcproperties 16,17,22 of lead and bismuth. Pb Bi Atomic numberdifferences in bismuth and lead plasmas: evidence for the

  10. Geochemical tracers of processes affecting the formation of seafloor hydrothermal fluids and deposits in the Manus back-arc basin

    E-Print Network [OSTI]

    Craddock, Paul R

    2009-01-01

    Systematic differences in trace element compositions (rare earth element (REE), heavy metal, metalloid concentrations) of seafloor vent fluids and related deposits from hydrothermal systems in the Manus back-arc basin ...

  11. AUTOMOTIVE RESEARCH CENTER (ARC) A U.S. Army Center of Excellence for Modeling and Simulation of Ground Vehicles

    E-Print Network [OSTI]

    Awtar, Shorya

    Vehicles AU T OM OT IVE RESEA RC H CEN T ER ARC Seminar Jet Fuel ­ It's Not Just for Planes! Dr. Tim Edwards Senior Chemical Engineer Fuels Branch ­ Air Abstract: Jet fuel is traditionally thought of as the fuel

  12. Development of an ArcGIS interface and design of a geodatabase for the soil and water assessment tool 

    E-Print Network [OSTI]

    Valenzuela Zapata, Milver Alfredo

    2004-09-30

    This project presents the development and design of a comprehensive interface coupled with a geodatabase (ArcGISwat 2003), for the Soil and Water Assessment Tool (SWAT). SWAT is a hydrologically distributed, lumped parameter model that runs on a...

  13. Thermal protection of H13 steel by growth of (TiAl)N films by PAPVD pulsed arc technique

    SciTech Connect (OSTI)

    Jimenez, H.; Devia, D.M.; Benavides, V.; Devia, A. Arango, Y.C.; Arango, P.J.; Velez, J.M.

    2008-08-15

    (TiAl)N Films were grown on H13 steel by a plasma assisted repetitive pulsed arc discharge. To grow the coatings, a TiAl sintered cathode was used, 50% Ti-50% Al. The deposition system consists of a reaction chamber with two electrodes placed face to face. A pulsed power supply, which allows for control of parameters like time active arc, time between arcs, arc energy, and others, is used to generate the discharge. Thermal changes were carried out on H13 steel before and after growing the (TiAl)N films. X-ray diffraction (XRD) was employed to study the coatings, observing the H13 steel and (TiAl)N oxidation temperature. Morphological characteristics were analyzed by means of an Atomic Force Microscopy (AFM). Scanning electron microscopy (SEM) revealed the surface chemical composition of the films and morphological details of the samples.

  14. Control of Gas Tungsten Arc welding pool shape by trace element addition to the weld pool

    DOE Patents [OSTI]

    Heiple, C.R.; Burgardt, P.

    1984-03-13

    An improved process for Gas Tungsten Arc welding maximizes the depth/width ratio of the weld pool by adding a sufficient amount of a surface active element to insure inward fluid flow, resulting in deep, narrow welds. The process is especially useful to eliminate variable weld penetration and shape in GTA welding of steels and stainless steels, particularly by using a sulfur-doped weld wire in a cold wire feed technique.

  15. Miniature pulsed vacuum arc plasma gun and apparatus for thin-film fabrication

    DOE Patents [OSTI]

    Brown, I.G.; MacGill, R.A.; Galvin, J.E.; Ogletree, D.F.; Salmeron, M.

    1998-11-24

    A miniature (dime-size in cross-section) vapor vacuum arc plasma gun is described for use in an apparatus to produce thin films. Any conductive material can be layered as a film on virtually any substrate. Because the entire apparatus can easily be contained in a small vacuum chamber, multiple dissimilar layers can be applied without risk of additional contamination. The invention has special applications in semiconductor manufacturing. 8 figs.

  16. Miniature pulsed vacuum arc plasma gun and apparatus for thin-film fabrication

    DOE Patents [OSTI]

    Brown, Ian G. (Berkeley, CA); MacGill, Robert A. (Richmond, CA); Galvin, James E. (Emmeryville, CA); Ogletree, David F. (El Cerrito, CA); Salmeron, Miquel (El Cerrito, CA)

    1998-01-01

    A miniature (dime-size in cross-section) vapor vacuum arc plasma gun is described for use in an apparatus to produce thin films. Any conductive material can be layered as a film on virtually any substrate. Because the entire apparatus can easily be contained in a small vacuum chamber, multiple dissimilar layers can be applied without risk of additional contamination. The invention has special applications in semiconductor manufacturing.

  17. Exploring high temperature phenomena related to post-detonation using an electric arc

    SciTech Connect (OSTI)

    Dai, Z. R. Crowhurst, J. C.; Grant, C. D.; Knight, K. B.; Tang, V.; Chernov, A. A.; Cook, E. G.; Lotscher, J. P.; Hutcheon, I. D.

    2013-11-28

    We report a study of materials recovered from a uranium-containing plasma generated by an electric arc. The device used to generate the arc is capable of sustaining temperatures of an eV or higher for up to 100??s. Samples took the form of a 4??m-thick film deposited onto 8 pairs of 17??m-thick Cu electrodes supported on a 25??m-thick Kapton backing and sandwiched between glass plates. Materials recovered from the glass plates and around the electrode tips after passage of an arc were characterized using scanning and transmission electron microscopy. Recovered materials included a variety of crystalline compounds (e.g., UO{sub 2}, UC{sub 2}, UCu{sub 5},) as well as mixtures of uranium and amorphous glass. Most of the materials collected on the glass plates took the form of spherules having a wide range of diameters from tens of nanometers to tens of micrometers. The composition and size of the spherules depended on location, indicating different chemical and physical environments. A theoretical analysis we have carried out suggests that the submicron spherules presumably formed by deposition during the arc discharge, while at the same time the glass plates were strongly heated due to absorption of plasma radiation mainly by islands of deposited metals (Cu, U). The surface temperature of the glass plates is expected to have risen to ?2300?K thus producing a liquefied glass layer, likely diffusions of the deposited metals on the hot glass surface and into this layer were accompanied by chemical reactions that gave rise to the observed materials. These results, together with the compact scale and relatively low cost, suggest that the experimental technique provides a practical approach to investigate the complex physical and chemical processes that occur when actinide-containing material interacts with the environment at high temperature, for example, during fallout formation following a nuclear detonation.

  18. Analytical expression for the electric potential in the plasma sheath near an arc-cathode

    SciTech Connect (OSTI)

    Askari, S.; Minoo, H.

    2008-04-15

    An expression for the spatial dependence of the electric potential in a collisionless plasma sheath near an electron-emitting cathode is presented. The applicability of this expression for an arc cathode is demonstrated. Comparison with the numerical solutions of the model equations indicates that the sheath thickness and potential variation predicted by this expression are accurate in a wide range of the electron-emission yield.

  19. Solid oxide fuel cell processing using plasma arc spray deposition techniques. Final report

    SciTech Connect (OSTI)

    Ray, E.R.; Spengler, C.J.; Herman, H.

    1991-07-01

    The Westinghouse Electric Corporation, in conjunction with the Thermal Spray Laboratory of the State University of New York, Stony Brook, investigated the fabrication of a gas-tight interconnect layer on a tubular solid oxide fuel cell with plasma arc spray deposition. The principal objective was to determine the process variables for the plasma spray deposition of an interconnect with adequate electrical conductivity and other desired properties. Plasma arc spray deposition is a process where the coating material in powder form is heated to or above its melting temperature, while being accelerated by a carrier gas stream through a high power electric arc. The molten powder particles are directed at the substrate, and on impact, form a coating consisting of many layers of overlapping, thin, lenticular particles or splats. The variables investigated were gun power, spray distance, powder feed rate, plasma gas flow rates, number of gun passes, powder size distribution, injection angle of powder into the plasma plume, vacuum or atmospheric plasma spraying, and substrate heating. Typically, coatings produced by both systems showed bands of lanthanum rich material and cracking with the coating. Preheating the substrate reduced but did not eliminate internal coating cracking. A uniformly thick, dense, adherent interconnect of the desired chemistry was finally achieved with sufficient gas- tightness to allow fabrication of cells and samples for measurement of physical and electrical properties. A cell was tested successfully at 1000{degree}C for over 1,000 hours demonstrating the mechanical, electrical, and chemical stability of a plasma-arc sprayed interconnect layer.

  20. Solid oxide fuel cell processing using plasma arc spray deposition techniques

    SciTech Connect (OSTI)

    Ray, E.R.; Spengler, C.J.; Herman, H.

    1991-07-01

    The Westinghouse Electric Corporation, in conjunction with the Thermal Spray Laboratory of the State University of New York, Stony Brook, investigated the fabrication of a gas-tight interconnect layer on a tubular solid oxide fuel cell with plasma arc spray deposition. The principal objective was to determine the process variables for the plasma spray deposition of an interconnect with adequate electrical conductivity and other desired properties. Plasma arc spray deposition is a process where the coating material in powder form is heated to or above its melting temperature, while being accelerated by a carrier gas stream through a high power electric arc. The molten powder particles are directed at the substrate, and on impact, form a coating consisting of many layers of overlapping, thin, lenticular particles or splats. The variables investigated were gun power, spray distance, powder feed rate, plasma gas flow rates, number of gun passes, powder size distribution, injection angle of powder into the plasma plume, vacuum or atmospheric plasma spraying, and substrate heating. Typically, coatings produced by both systems showed bands of lanthanum rich material and cracking with the coating. Preheating the substrate reduced but did not eliminate internal coating cracking. A uniformly thick, dense, adherent interconnect of the desired chemistry was finally achieved with sufficient gas- tightness to allow fabrication of cells and samples for measurement of physical and electrical properties. A cell was tested successfully at 1000{degree}C for over 1,000 hours demonstrating the mechanical, electrical, and chemical stability of a plasma-arc sprayed interconnect layer.

  1. An arc control and protection system for the JET lower hybrid antenna based on an imaging system

    SciTech Connect (OSTI)

    Figueiredo, J.

    2014-11-15

    Arcs are the potentially most dangerous events related to Lower Hybrid (LH) antenna operation. If left uncontrolled they can produce damage and cause plasma disruption by impurity influx. To address this issue an arc real time control and protection imaging system for the Joint European Torus (JET) LH antenna has been implemented. The LH system is one of the additional heating systems at JET. It comprises 24 microwave generators (klystrons, operating at 3.7 GHz) providing up to 5 MW of heating and current drive to the JET plasma. This is done through an antenna composed of an array of waveguides facing the plasma. The protection system presented here is based primarily on an imaging arc detection and real time control system. It has adapted the ITER like wall hotspot protection system using an identical CCD camera and real time image processing unit. A filter has been installed to avoid saturation and spurious system triggers caused by ionization light. The antenna is divided in 24 Regions Of Interest (ROIs) each one corresponding to one klystron. If an arc precursor is detected in a ROI, power is reduced locally with subsequent potential damage and plasma disruption avoided. The power is subsequently reinstated if, during a defined interval of time, arcing is confirmed not to be present by image analysis. This system was successfully commissioned during the restart phase and beginning of the 2013 scientific campaign. Since its installation and commissioning, arcs and related phenomena have been prevented. In this contribution we briefly describe the camera, image processing, and real time control systems. Most importantly, we demonstrate that an LH antenna arc protection system based on CCD camera imaging systems works. Examples of both controlled and uncontrolled LH arc events and their consequences are shown.

  2. Laser-ultrasonic inspection of hybrid laser-arc welded HSLA-65 steel

    SciTech Connect (OSTI)

    Lévesque, D.; Rousseau, G.; Monchalin, J.-P. [National Research Council Canada, Boucherville, QC (Canada); Wanjara, P.; Cao, X. [National Research Council Canada, Montreal, QC (Canada)

    2014-02-18

    The hybrid laser-arc welding (HLAW) process is a relatively low heat input joining technology that combines the synergistic qualities of both the high energy density laser beam for deep penetration and the arc for wide fit-up gap tolerance. This process is especially suitable for the shipbuilding industry where thick-gauge section, long steel plates have been widely used in a butt joint configuration. In this study, preliminary exploration was carried out to detect and visualize the welding defects using laser ultrasonics combined with the synthetic aperture focusing technique (SAFT). Results obtained on 9.3 mm thick butt-welded HSLA-65 steel plates indicated that the laser-ultrasonic SAFT inspection technique can successfully detect and visualize the presence of porosity, lack of fusion and internal crack defects. This was further confirmed by X-ray digital radiography and metallography. The results obtained clearly show the potential of using the laser-ultrasonic technology for the automated inspection of hybrid laser-arc welds.

  3. Arc plasma generator of atomic driver for steady-state negative ion source

    SciTech Connect (OSTI)

    Ivanov, A. A.; Belchenko, Yu. I.; Davydenko, V. I.; Novosibirsk State University, Novosibirsk ; Ivanov, I. A.; Kolmogorov, V. V.; Listopad, A. A. Mishagin, V. V.; Shulzhenko, G. I.; Putvinsky, S. V.; Smirnov, A.

    2014-02-15

    The paper reviews the results of development of steady-state arc-discharge plasma generator with directly heated LaB{sub 6} cathode. This arc-discharge plasma generator produces a plasma jet which is to be converted into an atomic one after recombination on a metallic plate. The plate is electrically biased relative to the plasma in order to control the atom energies. Such an intensive jet of hydrogen atoms can be used in negative ion sources for effective production of negative ions on a cesiated surface of plasma grid. All elements of the plasma generator have an augmented water cooling to operate in long pulse mode or in steady state. The thermo-mechanical stresses and deformations of the most critical elements of the plasma generator were determined by simulations. Magnetic field inside the discharge chamber was optimized to reduce the local power loads. The first tests of the steady-state arc plasma generator prototype have performed in long-pulse mode.

  4. Preliminary photovoltaic arc-fault prognostic tests using sacrificial fiber optic cabling.

    SciTech Connect (OSTI)

    Johnson, Jay; Blemel, Kenneth D.; Peter, Francis

    2013-02-01

    Through the New Mexico Small Business Assistance Program, Sandia National Laboratories worked with Sentient Business Systems, Inc. to develop and test a novel photovoltaic (PV) arc-fault detection system. The system operates by pairing translucent polymeric fiber optic sensors with electrical circuitry so that any external abrasion to the system or internal heating causes the fiber optic connection to fail or detectably degrade. A periodic pulse of light is sent through the optical path using a transmitter-receiver pair. If the receiver does not detect the pulse, an alarm is sounded and the PV system can be de-energized. This technology has the unique ability to prognostically determine impending failures to the electrical system in two ways: (a) the optical connection is severed prior to physical abrasion or cutting of PV DC electrical conductors, and (b) the polymeric fiber optic cable melts via Joule heating before an arc-fault is established through corrosion. Three arc-faults were created in different configurations found in PV systems with the integrated fiber optic system to determine the feasibility of the technology. In each case, the fiber optic cable was broken and the system annunciated the fault.

  5. Statistical analysis of multipole components in the magnetic field of the RHIC arc regions

    SciTech Connect (OSTI)

    Beebe-Wang,J.; Jain, A.

    2009-05-04

    The existence of multipolar components in the dipole and quadrupole magnets is one of the factors limiting the beam stability in the RHIC operations. Therefore, the statistical properties of the non-linear fields are crucial for understanding the beam behavior and for achieving the superior performance in RHIC. In an earlier work [1], the field quality analysis of the RHIC interaction regions (IR) was presented. Furthermore, a procedure for developing non-linear IR models constructed from measured multipolar data of RHIC IR magnets was described. However, the field quality in the regions outside of the RHIC IR had not yet been addressed. In this paper, we present the statistical analysis of multipolar components in the magnetic fields of the RHIC arc regions. The emphasis is on the lower order components, especially the sextupole in the arc dipole and the 12-pole in the quadrupole magnets, since they are shown to have the strongest effects on the beam stability. Finally, the inclusion of the measured multipolar components data of RHIC arc regions and their statistical properties into tracking models is discussed.

  6. Pressure and arc voltage coupling in dc plasma torches: Identification and extraction of oscillation modes

    SciTech Connect (OSTI)

    Rat, V.; Coudert, J. F.

    2010-08-15

    This work is devoted to the instabilities occurring in a plasma torch, such as those found in plasma spraying. These instabilities are responsible for a lack of reproducibility of coatings properties, especially in the case of suspension plasma spraying that is an innovative way to obtain thin coatings of submicron-sized particles. Strong Helmholtz oscillations are highlighted in the plasma flow and it is demonstrated that they overlap with different acoustic modes in addition with the more commonly admitted ''restrike'' mode, the later being due to rearcing events in the arc region. The instabilities occur in the arc voltage but it is experimentally shown in this paper that the pressure within the torch body presents the same kind of instabilities. Besides, a numerical filtering technique has been adapted to isolate the different instability components. The operating parameters of the plasma torch were varied in order to highlight their influence on the amplitude of the different modes, both for the arc voltage and the pressure.

  7. Modeling of Interstellar Scintillation Arcs from Pulsar B1133+16

    E-Print Network [OSTI]

    Frank S. Trang; Barney J. Rickett

    2007-02-07

    The parabolic arc phenomenon visible in the Fourier analysis of the scintillation spectra of pulsars provides a new method of investigating the small scale structure in the ionized interstellar medium (ISM). We report archival observations of the pulsar B1133+16 showing both forward and reverse parabolic arcs sampled over 14 months. These features can be understood as the mutual interference between an assembly of discrete features in the scattered brightness distribution. By model-fitting to the observed arcs at one epoch we obtain a ``snap-shot'' estimate of the scattered brightness, which we show to be highly anisotropic (axial ratio >10:1), to be centered significantly off axis and to have a small number of discrete maxima, which are coarser the speckle expected from a Kolmogorov spectrum of interstellar plasma density. The results suggest the effects of highly localized discrete scattering regions which subtend 0.1-1 mas, but can scatter (or refract) the radiation by angles that are five or more times larger.

  8. Optimization of the output and efficiency of a high power cascaded arc hydrogen plasma source

    SciTech Connect (OSTI)

    Vijvers, W. A. J.; Gils, C. A. J. van; Goedheer, W. J.; Meiden, H. J. van der; Veremiyenko, V. P.; Westerhout, J.; Lopes Cardozo, N. J.; Rooij, G. J. van; Schram, D. C.

    2008-09-15

    The operation of a cascaded arc hydrogen plasma source was experimentally investigated to provide an empirical basis for the scaling of this source to higher plasma fluxes and efficiencies. The flux and efficiency were determined as a function of the input power, discharge channel diameter, and hydrogen gas flow rate. Measurements of the pressure in the arc channel show that the flow is well described by Poiseuille flow and that the effective heavy particle temperature is approximately 0.8 eV. Interpretation of the measured I-V data in terms of a one-parameter model shows that the plasma production is proportional to the input power, to the square root of the hydrogen flow rate, and is independent of the channel diameter. The observed scaling shows that the dominant power loss mechanism inside the arc channel is one that scales with the effective volume of the plasma in the discharge channel. Measurements on the plasma output with Thomson scattering confirm the linear dependence of the plasma production on the input power. Extrapolation of these results shows that (without a magnetic field) an improvement in the plasma production by a factor of 10 over where it was in van Rooij et al. [Appl. Phys. Lett. 90, 121501 (2007)] should be possible.

  9. Mechanism of Synthesis of Ultra-Long Single Wall Carbon Nanotubes in Arc Discharge Plasma

    SciTech Connect (OSTI)

    Keidar, Michael

    2013-06-23

    In this project fundamental issues related to synthesis of single wall carbon nanotubes (SWNTs), which is relationship between plasma parameters and SWNT characteristics were investigated. Given that among plasma-based techniques arc discharge stands out as very advantageous in several ways (fewer defects, high flexibility, longer lifetime) this techniques warrants attention from the plasma physics and plasma technology standpoint. Both experimental and theoretical investigations of the plasma and SWNTs synthesis were conducted. Experimental efforts focused on plasma diagnostics, measurements of nanostructures parameters, and nanoparticle characterization. Theoretical efforts focused to focus on multi-dimensional modeling of the arc discharge and single wall nanotube synthesis in arc plasmas. It was demonstrated in experiment and theoretically that controlling plasma parameters can affect nanostucture synthesis altering SWNT properties (length and diameter) and leading to synthesis of new structures such as a few-layer graphene. Among clearly identified parameters affecting synthesis are magnetic and electric fields. Knowledge of the plasma parameters and discharge characteristics is crucial for ability to control synthesis process by virtue of both magnetic and electric fields. New graduate course on plasma engineering was introduced into curriculum. 3 undergraduate students were attracted to the project and 3 graduate students (two are female) were involved in the project. Undergraduate student from Historically Black University was attracted and participated in the project during Summer 2010.

  10. Effect of cerium ions in an arc peripheral plasma on the growth of radial single-walled carbon nanotubes

    SciTech Connect (OSTI)

    Sato, Y.; Motomiya, K.; Jeyadevan, B.; Tohji, K.; Sato, G.; Ishida, H.; Hirata, T.; Hatakeyama, R.

    2005-11-01

    Radial single-walled carbon nanotubes (radial SWCNTs) are formed by using a direct current (dc) arc discharge when carbon and metal atoms are mixed in a gas phase after the vaporization and cooled together in a liquid droplet. Since SWCNTs sprout through the precipitation of saturated carbon atoms from liquid droplets during cooling, a mass synthesis of radial SWCNTs can be achieved when a large number of liquid droplets are generated. In order to understand the effects of arc peripheral plasma parameters (electrons, ions, radical atoms, and molecules) on the growth of radial SWCNTs, the optimum production efficiency of radial SWCNTs is investigated by superimposing a radio-frequency (rf) plasma on the thermal arc plasma and controlling the arc peripheral plasma density. Two parameters--the rf power and the dc potential--of the rf electrode, which is equipped above 20 mm from the center of an arc-discharge point, are changed with the constant He pressure (200 Torr), dc arc current (75 A), and power (2000 W). The production yield of radial SWCNTs is found to be enhanced under the condition of the rf power of 100 W and the dc component of the rf electrode voltage of -22 V, revealing that the optimum ion flux and ion bombardment energy are important key parameters for the formation of radial SWCNTs.

  11. Evaluation of Cooling Conditions for a High Heat Flux Testing Facility Based on Plasma-Arc Lamps

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Charry, Carlos H.; Abdel-khalik, Said I.; Yoda, Minami; Sabau, Adrian S.; Snead, Lance Lewis

    2015-07-31

    The new Irradiated Material Target Station (IMTS) facility for fusion materials at Oak Ridge National Laboratory (ORNL) uses an infrared plasma-arc lamp (PAL) to deliver incident heat fluxes as high as 27 MW/m2. The facility is being used to test irradiated plasma-facing component materials as part of the joint US-Japan PHENIX program. The irradiated samples are to be mounted on molybdenum sample holders attached to a water-cooled copper rod. Depending on the size and geometry of samples, several sample holders and copper rod configurations have been fabricated and tested. As a part of the effort to design sample holders compatiblemore »with the high heat flux (HHF) testing to be conducted at the IMTS facility, numerical simulations have been performed for two different water-cooled sample holder designs using the ANSYS FLUENT 14.0 commercial computational fluid dynamics (CFD) software package. The primary objective of this work is to evaluate the cooling capability of different sample holder designs, i.e. to estimate their maximum allowable incident heat flux values. 2D axisymmetric numerical simulations are performed using the realizable k-? turbulence model and the RPI nucleate boiling model within ANSYS FLUENT 14.0. The results of the numerical model were compared against the experimental data for two sample holder designs tested in the IMTS facility. The model has been used to parametrically evaluate the effect of various operational parameters on the predicted temperature distributions. The results were used to identify the limiting parameter for safe operation of the two sample holders and the associated peak heat flux limits. The results of this investigation will help guide the development of new sample holder designs.« less

  12. Evaluation of Cooling Conditions for a High Heat Flux Testing Facility Based on Plasma-Arc Lamps

    SciTech Connect (OSTI)

    Charry, Carlos H.; Abdel-khalik, Said I.; Yoda, Minami; Sabau, Adrian S.; Snead, Lance Lewis

    2015-07-31

    The new Irradiated Material Target Station (IMTS) facility for fusion materials at Oak Ridge National Laboratory (ORNL) uses an infrared plasma-arc lamp (PAL) to deliver incident heat fluxes as high as 27 MW/m2. The facility is being used to test irradiated plasma-facing component materials as part of the joint US-Japan PHENIX program. The irradiated samples are to be mounted on molybdenum sample holders attached to a water-cooled copper rod. Depending on the size and geometry of samples, several sample holders and copper rod configurations have been fabricated and tested. As a part of the effort to design sample holders compatible with the high heat flux (HHF) testing to be conducted at the IMTS facility, numerical simulations have been performed for two different water-cooled sample holder designs using the ANSYS FLUENT 14.0 commercial computational fluid dynamics (CFD) software package. The primary objective of this work is to evaluate the cooling capability of different sample holder designs, i.e. to estimate their maximum allowable incident heat flux values. 2D axisymmetric numerical simulations are performed using the realizable k-? turbulence model and the RPI nucleate boiling model within ANSYS FLUENT 14.0. The results of the numerical model were compared against the experimental data for two sample holder designs tested in the IMTS facility. The model has been used to parametrically evaluate the effect of various operational parameters on the predicted temperature distributions. The results were used to identify the limiting parameter for safe operation of the two sample holders and the associated peak heat flux limits. The results of this investigation will help guide the development of new sample holder designs.

  13. Laser-Arc Hybrid Welding of Thick Section Ni-base Alloys – Advanced Modeling and Experiments

    SciTech Connect (OSTI)

    Debroy, Tarasankar; Palmer, Todd; Zhang, Wei

    2015-05-21

    Hybrid laser-arc welding of nickel-base alloys can increase productivity and decrease costs during construction and repair of critical components in nuclear power plants. However, laser and hybrid welding of nickel-base alloys is not well understood. This project sought to understand the physical processes during hybrid welding necessary to fabricate quality joints in Alloy 690, a Ni- Cr-Fe alloy. This document presents a summary of the data and results collected over the course of the project. The supporting documents are a collection of the research that has been or will be published in peer-reviewed journals along with a report from the partner at the national lab. Understanding the solidification behavior of Alloy 690 is important for knowing the final properties of the weldment. A study was undertaken to calculate the solidification parameters, such as temperature gradient, solidification rate, and cooling rate in Alloy 690 welds. With this information and measured cell and dendrite arm spacings, an Alloy 690 map was constructed to guide process parameter development and interpret fusion zones in later hybrid welds. This research is contained in “Solidification Map of a Nickel Base Alloy.” The keyhole formed under high laser intensity gives the hybrid welding technique the greater penetration depths compared to arc welding. However, keyhole behavior can form defects in the material, so knowing transient keyhole characteristics is important. With international collaborators, a study was undertaken to validate a new process monitoring tool known as inline coherent imaging (ICI), which is able to measure the keyhole depth with spatial and temporal resolutions on the order of 10 microns and 10 microseconds. ICI was validated for five alloy systems, including Alloy 690. Additionally, the keyhole growth rates at the start of welding were measured with unprecedented accuracy. This research is contained in “Real Time Monitoring of Laser Beam Welding Keyhole Depth by Laser Interferometry.” During full penetration welding of thick sections, root defects can form, which result in unacceptable weld quality. A study was undertaken to determine the competing forces in root defect formation by independently changing the weight forces and surface tension forces. The weight force was altered by changing the plate thickness, and the surface tension force was altered by changing the surface condition at the bottom surface. Root defects do depend on these two forces. This research is contained in “Mitigation of Root Defect in Laser and Hybrid Laser-Arc Welding.” Validation of the hybrid laser-arc model is necessary to properly model heat and mass transfer and fluid flow in Alloy 690 hybrid welds. Therefore, the developed model was validated for low carbon steel. Temperatures calculated by the model were included into a microstructural model in order to calculate the phase fractions. Process maps were developed for the selection of welding parameters to avoid martensite formation. This research is contained in “Fusion Zone Microstructure in Full Penetration Laser-Arc Hybrid Welding of Low Alloy Steel.” Alloy 690 suffers from ductility dip cracking, a form of hot cracking. This type of cracking inhibits the use of multipass welding to join Alloy 690. Our partners at ORNL performed some hot ductility testing with Alloy 690 samples using digital image correlation. The results of this work is contained in the report “Summary of 690 ductility dip cracking testing using Gleeble and digital image correlation.” Macro-porosity is a limiting factor in the widespread deployment of laser and hybrid laser-arc welding for construction and repair of nuclear power plant components. Keyhole instability and fluctuation results in the formation of large bubbles, which become trapped at the advancing solid- liquid interface as pores. Laser and hybrid laser-arc welds were fabricated for a range of conditions. Porosity levels in the welds were measured in X-ray computed tomography (CT), which provides very detailed data on the size and lo

  14. Sandia Energy - Scattering Dynamics

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Scattering Dynamics Home Transportation Energy Predictive Simulation of Engines Combustion Chemistry Chemical Dynamics Scattering Dynamics Scattering DynamicsAshley...

  15. Characterization of Ion Species Mix of the Textor Diagnostic Hydrogen Beam Injector with an RF and Arc-discharge Plasma Box

    E-Print Network [OSTI]

    Ivanov, A A; Kreter, A; Maximov, V V; Podmonogin, A A; Schweer, B; Shikhoutsev, I V; Stupishin, N V; Uhlemann, R; Usoltsev, D V

    2002-01-01

    Characterization of Ion Species Mix of the Textor Diagnostic Hydrogen Beam Injector with an RF and Arc-discharge Plasma Box

  16. SU-E-T-539: Fixed Versus Variable Optimization Points in Combined-Mode Modulated Arc Therapy Planning

    SciTech Connect (OSTI)

    Kainz, K; Prah, D; Ahunbay, E; Li, X

    2014-06-01

    Purpose: A novel modulated arc therapy technique, mARC, enables superposition of step-and-shoot IMRT segments upon a subset of the optimization points (OPs) of a continuous-arc delivery. We compare two approaches to mARC planning: one with the number of OPs fixed throughout optimization, and another where the planning system determines the number of OPs in the final plan, subject to an upper limit defined at the outset. Methods: Fixed-OP mARC planning was performed for representative cases using Panther v. 5.01 (Prowess, Inc.), while variable-OP mARC planning used Monaco v. 5.00 (Elekta, Inc.). All Monaco planning used an upper limit of 91 OPs; those OPs with minimal MU were removed during optimization. Plans were delivered, and delivery times recorded, on a Siemens Artiste accelerator using a flat 6MV beam with 300 MU/min rate. Dose distributions measured using ArcCheck (Sun Nuclear Corporation, Inc.) were compared with the plan calculation; the two were deemed consistent if they agreed to within 3.5% in absolute dose and 3.5 mm in distance-to-agreement among > 95% of the diodes within the direct beam. Results: Example cases included a prostate and a head-and-neck planned with a single arc and fraction doses of 1.8 and 2.0 Gy, respectively. Aside from slightly more uniform target dose for the variable-OP plans, the DVHs for the two techniques were similar. For the fixed-OP technique, the number of OPs was 38 and 39, and the delivery time was 228 and 259 seconds, respectively, for the prostate and head-and-neck cases. For the final variable-OP plans, there were 91 and 85 OPs, and the delivery time was 296 and 440 seconds, correspondingly longer than for fixed-OP. Conclusion: For mARC, both the fixed-OP and variable-OP approaches produced comparable-quality plans whose delivery was successfully verified. To keep delivery time per fraction short, a fixed-OP planning approach is preferred.

  17. Sci—Thur AM: YIS - 04: Gold Nanoparticle Enhanced Arc Radiotherapy: A Monte Carlo Feasibility Study

    SciTech Connect (OSTI)

    Koger, B; Kirkby, C

    2014-08-15

    Introduction: The use of gold nanoparticles (GNPs) in radiotherapy has shown promise for therapeutic enhancement. In this study, we explore the feasibility of enhancing radiotherapy with GNPs in an arc-therapy context. We use Monte Carlo simulations to quantify the macroscopic dose-enhancement ratio (DER) and tumour to normal tissue ratio (TNTR) as functions of photon energy over various tumour and body geometries. Methods: GNP-enhanced arc radiotherapy (GEART) was simulated using the PENELOPE Monte Carlo code and penEasy main program. We simulated 360° arc-therapy with monoenergetic photon energies 50 – 1000 keV and several clinical spectra used to treat a spherical tumour containing uniformly distributed GNPs in a cylindrical tissue phantom. Various geometries were used to simulate different tumour sizes and depths. Voxel dose was used to calculate DERs and TNTRs. Inhomogeneity effects were examined through skull dose in brain tumour treatment simulations. Results: Below 100 keV, DERs greater than 2.0 were observed. Compared to 6 MV, tumour dose at low energies was more conformai, with lower normal tissue dose and higher TNTRs. Both the DER and TNTR increased with increasing cylinder radius and decreasing tumour radius. The inclusion of bone showed excellent tumour conformality at low energies, though with an increase in skull dose (40% of tumour dose with 100 keV compared to 25% with 6 MV). Conclusions: Even in the presence of inhomogeneities, our results show promise for the treatment of deep-seated tumours with low-energy GEART, with greater tumour dose conformality and lower normal tissue dose than 6 MV.

  18. Formation of NOx precursors during Chinese pulverized coal pyrolysis in an arc plasma jet

    SciTech Connect (OSTI)

    Wei-ren Bao; Jin-cao Zhang; Fan Li; Li-ping Chang

    2007-08-15

    The formation of NOx precursors (HCN and NH{sub 3}) from the pyrolysis of several Chinese pulverized coals in an arc plasma jet was investigated through both thermodynamic analysis of the C-H-O-N system and experiments. Results of thermodynamic analysis show that the dominant N-containing gaseous species is HCN together with a small amount of ammonia above the temperature of 2000 K. The increase of H content advances the formation of HCN and NH{sub 3}, but the yields of HCN and NH{sub 3} are decreased with a high concentration of O in the system. These results are accordant with the experimental data. The increasing of input power promotes the formation of HCN and NH{sub 3} from coal pyrolysis in an arc plasma jet. Tar-N is not formed during the process. The yield of HCN changes insignificantly with the changing of the residence time of coal particles in the reactor, but that of NH{sub 3} decreases as residence times increase because of the relative instability at high temperature. Adsorption and gasification of CO{sub 2} on the coal surface also can restrain the formation of HCN and NH{sub 3} compare to the results in an Ar plasma jet. Yields of HCN and NH{sub 3} are sensitive to the coal feeding rate, indicating that NOx precursors could interact with the nascent char to form other N-containing species. The formation of HCN and NH{sub 3} during coal pyrolysis in a H{sub 2}/Ar plasma jet are not dependent on coal rank. The N-containing gaseous species is released faster than others in the volatiles during coal pyrolysis in an arc plasma jet, and the final nitrogen content in the char is lower than that in the parent coal, which it is independent of coal type. 16 refs., 9 figs., 1 tab.

  19. Boron Ion Implantation into Silicon by Use of the Boron Vacuum-Arc Plasma Generator

    SciTech Connect (OSTI)

    Williams, J. M.; Klepper, C. C.; Chivers, D. J.; Hazelton, R. C.; Moschella, J. J.; Keitz, M. D.

    2006-11-13

    This paper continues with presentation of experimental work pertaining to use of the boron vacuum arc (a.k.a. cathodic arc) plasma generator for boron doping in semiconductor silicon, particularly with a view to the problems associated with shallow junction doping. Progress includes development of an excellent and novel macroparticle filter and subsequent ion implantations. An important perceived issue for vacuum arc generators is the production of copious macroparticles from cathode material. This issue is more important for cathodes of materials such as carbon or boron, for which the particles are not molten or plastic, but instead are elastic, and tend to recoil from baffles used in particle filters. The present design starts with two vanes of special orientation, so as to back reflect the particles, while steering the plasma between the vanes by use of high countercurrents in the vanes. Secondly, behind and surrounding the vanes is a complex system of baffles that has been designed by a computer-based strategy to ultimately trap the particles for multiple bounces. The statistical transmittance of particles is less than 5 per coulomb of boron ions transmitted at a position just a few centimeters outside the filter. This value appears adequate for the silicon wafer application, but improvement is easily visualized as wafers will be situated much further away when they are treated in systems. A total of 11 silicon samples, comprising an area of 250 cm2, have been implanted. Particles were not detected. Sample biases ranged from 60 to 500 V. Boron doses ranged from 5 x 1014 to 5 x 1015/cm2. Exposure times ranged from 20 to 200 ms for average transmitted boron current values of about 125 mA. SIMS concentration profiles from crystalline material are presented. The results appear broadly favorable in relation to competitive techniques and will be discussed. It is concluded that doubly charged boron ions are not present in the plume.

  20. SpArcFiRe: Scalable automated detection of spiral galaxy arm segments

    SciTech Connect (OSTI)

    Davis, Darren R.; Hayes, Wayne B., E-mail: drdavis@uci.edu, E-mail: whayes@uci.edu [University of California, Irvine, CA 92697-3435 (United States)

    2014-08-01

    Given an approximately centered image of a spiral galaxy, we describe an entirely automated method that finds, centers, and sizes the galaxy (possibly masking nearby stars and other objects if necessary in order to isolate the galaxy itself) and then automatically extracts structural information about the spiral arms. For each arm segment found, we list the pixels in that segment, allowing image analysis on a per-arm-segment basis. We also perform a least-squares fit of a logarithmic spiral arc to the pixels in that segment, giving per-arc parameters, such as the pitch angle, arm segment length, location, etc. The algorithm takes about one minute per galaxies, and can easily be scaled using parallelism. We have run it on all ?644,000 Sloan objects that are larger than 40 pixels across and classified as 'galaxies'. We find a very good correlation between our quantitative description of a spiral structure and the qualitative description provided by Galaxy Zoo humans. Our objective, quantitative measures of structure demonstrate the difficulty in defining exactly what constitutes a spiral 'arm', leading us to prefer the term 'arm segment'. We find that pitch angle often varies significantly segment-to-segment in a single spiral galaxy, making it difficult to define the pitch angle for a single galaxy. We demonstrate how our new database of arm segments can be queried to find galaxies satisfying specific quantitative visual criteria. For example, even though our code does not explicitly find rings, a good surrogate is to look for galaxies having one long, low-pitch-angle arm—which is how our code views ring galaxies. SpArcFiRe is available at http://sparcfire.ics.uci.edu.

  1. Low Cost Arc Fault Detection and Protection for PV Systems: January 30, 2012 - September 30, 2013

    SciTech Connect (OSTI)

    McCalmont, S.

    2013-10-01

    Final report for Tigo Energy Incubator project. The specific objective of this 18-month research effort was to develop an off-the-shelf arc-fault detector. The starting point of the project was a prototype detector that was constructed using discrete components and laboratory equipment. An intermediate objective was to build a technically viable detector using programmable components in the detector circuitry. The final objective was to build a commercially viable detector by reducing the cost of the circuitry through the use of more sophisticated programmable components and higher levels of integration.

  2. Fermi arcs vs. fermi pockets in electron-doped perovskite iridates

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    He, Junfeng; Hafiz, H.; Mion, Thomas R.; Hogan, T.; Dhital, C.; Oak Ridge National Lab.; Chen, X.; Lin, Qisen; Hashimoto, M.; Lu, D. H.; et al

    2015-02-23

    We report on an angle resolved photoemission (ARPES) study of bulk electron-doped perovskite iridate, (Sr1-xLax)?Ir?O?. Fermi surface pockets are observed with a total electron count in keeping with that expected from La substitution. Depending on the energy and polarization of the incident photons, these pockets show up in the form of disconnected “Fermi arcs”, reminiscent of those reported recently in surface electron-doped Sr?IrO?. Our observed spectral variation is consistent with the coexistence of an electronic supermodulation with structural distortion in the system.

  3. Influence of discharge gap on the discharge stability in a short vacuum arc ion source

    SciTech Connect (OSTI)

    Chen, L.; Zhang, G. L.; Jin, D. Z.; Dai, J. Y.; Yang, L.

    2012-02-15

    The influence of the discharge gap between cathode and anode on the discharge stability in a short vacuum arc (SVA) ion source is presented in this paper. Planar cathode and cylindrical hollow anode made of titanium are investigated. There is a great need in present accelerator injection research for SVA source to produce the small deviation of the ion current beam. Current research shows that increasing the short discharge gap can reduce the level of ion current deviation and ion charge deviation from 29% and 31% to 15% and 17%, respectively. A microplasma plume generation mechanism in SVA and scanning electron microscopic results can be used to explain this interesting phenomenon.

  4. Standard Practice for Measuring Plasma Arc Gas Enthalpy by Energy Balance

    E-Print Network [OSTI]

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This practice covers the measurement of total gas enthalpy of an electric-arc-heated gas stream by means of an overall system energy balance. This is sometimes referred to as a bulk enthalpy and represents an average energy content of the test stream which may differ from local values in the test stream. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  5. Shapes of Spectral Lines of Nonuniform Plasma of Electric Arc Discharge Between Copper Electrodes

    SciTech Connect (OSTI)

    Babich, Ida L.; Boretskij, Viacheslav F.; Veklich, Anatoly N.

    2007-09-28

    The radial profiles of the temperature and electron density in the plasma of the free burning electric arc between copper electrodes are studied by optical spectroscopy techniques. The electron density and the temperature in plasma as initial parameters were used in the calculation of the plasma composition in local thermodynamic equilibrium (LTE) assumption. We used the Saha's equation for copper, nitrogen and oxygen, dissociation equation for nitrogen and oxygen, the equation of plasma electrical neutrality and Dalton's law as well. So, it would be possible to determine the amounts of metal vapours in plasma.

  6. High-Density Plasma Arc Heating Studies of FePt Thin Films

    SciTech Connect (OSTI)

    Cole, Amanda C; Thompson, Gregory; Harrell, J. W.; Weston, James; Ott, Ronald D

    2006-01-01

    The effect of pulsed-thermal-processing with high-density plasma arc heating is discussed for 20 nm thick nanocrystalline FePt thin films. The dependence of the A1 {yields} L1{sub 0} phase transformation on pulsed time and radiant energy of the pulse is quantified through x-ray diffraction and alternating gradient magnetometry. For 100 ms and 250 ms pulse widths, the phase transformation was observed. Higher radiant energy densities resulted in a larger measured coercivity associated with the L1{sub 0} phase.

  7. The Radiative Transfer Of CH{sub 4}-N{sub 2} Plasma Arc

    SciTech Connect (OSTI)

    Benallal, R.; Liani, B.

    2008-09-23

    Any physical modelling of a circuit-breaker arc therefore requires an understanding of the radiated energy which is taken into account in the form of a net coefficient. The evaluation of the net emission coefficient is performed by the knowledge of the chemical plasma composition and the resolution of the radiative transfer equation. In this paper, the total radiation which escapes from a CH{sub 4}-N{sub 2} plasma is calculated in the temperature range between 5000 and 30000K on the assumption of a local thermodynamic equilibrium and we have studied the nitrogen effect in the hydrocarbon plasmas.

  8. Growth and characterization of AuN films through the pulsed arc technique

    SciTech Connect (OSTI)

    Devia, A. Castillo, H.A.; Benavides, V.J.; Arango, Y.C.; Quintero, J.H.

    2008-02-15

    AuN films were produced through the PAPVD (Plasma Assisted Physics Vapor Deposition) method, using the pulsed arc technique in a mono-vaporizer noncommercial system, which consists of a chamber with two faced electrodes, and a power controlled system. In order to obtain the films, an Au Target with 99% purity and stainless steel 304 were used as target and substrate respectively. Nitrogen was injected in gaseous phase at 2.3 mbar pressure, and a discharge of 160 V was performed, supplied by the power controlled source. Au4f and N1s narrow spectra were analyzed using XPS (X-ray Photoelectron Spectroscopy)

  9. An Experimental Investigation of the Static and Dynamic Performance of Horizontal-Application and Vertical-Application Three-Lobe Bearings 

    E-Print Network [OSTI]

    Khatri, Rasish

    2014-08-07

    °, 90°, and 100°. This bearing has the following specifications: 100° pad arc angle, 0.52 preload, 70% offset, 101.74 mm (4.0057 in) minimum bore diameter, 0.116 mm (7.55 mils) radial pad clearance, and 76.3 mm (3 in) axial length. The static and dynamic...

  10. Study of Mechanical Properties and Characterization of Pipe Steel welded by Hybrid (Friction Stir Weld + Root Arc Weld) Approach

    SciTech Connect (OSTI)

    Lim, Yong Chae [ORNL; Sanderson, Samuel [MegaStir Technologies LLC; Mahoney, Murray [Consultant; Wasson, Andrew J [ExxonMobil, Upstream Research Company (URC); Fairchild, Doug P [ExxonMobil, Upstream Research Company (URC); Wang, Yanli [ORNL; Feng, Zhili [ORNL

    2015-01-01

    Friction stir welding (FSW) has recently attracted attention as an alternative construction process for gas/oil transportation applications due to advantages compared to fusion welding techniques. A significant advantage is the ability of FSW to weld the entire or nearly the entire wall thickness in a single pass, while fusion welding requires multiple passes. However, when FSW is applied to a pipe or tube geometry, an internal back support anvil is required to resist the plunging forces exerted during FSW. Unfortunately, it may not be convenient or economical to use internal backing support due to limited access for some applications. To overcome this issue, ExxonMobil recently developed a new concept, combining root arc welding and FSW. That is, a root arc weld is made prior to FSW that supports the normal loads associated with FSW. In the present work, mechanical properties of a FSW + root arc welded pipe steel are reported including microstructure and microhardness.

  11. On the mechanism of operation of a cathode spot cell in a vacuum arc

    SciTech Connect (OSTI)

    Mesyats, G. A.; Petrov, A. A.; Bochkarev, M. B.; Barengolts, S. A.

    2014-05-05

    The erosive structures formed on a tungsten cathode as a result of the motion of the cathode spot of a vacuum arc over the cathode surface have been examined. It has been found that the average mass of a cathode microprotrusion having the shape of a solidified jet is approximately equal to the mass of ions removed from the cathode within the lifetime of a cathode spot cell carrying a current of several amperes. The time of formation of a new liquid-metal jet under the action of the reactive force of the plasma ejected by the cathode spot is about 10?ns, which is comparable to the lifetime of a cell. The growth rate of a liquid-metal jet is ?10{sup 4}?cm/s. The geometric shape and size of a solidified jet are such that a new explosive emission center (spot cell) can be initiated within several nanoseconds during the interaction of the jet with the dense cathode plasma. This is the underlying mechanism of the self-sustained operation of a vacuum arc.

  12. Synthesis and characterization of carbon-encapsulated magnetic nanoparticles via arc-plasma assisted CVD

    SciTech Connect (OSTI)

    Li, Z.T.; Hu, C.; Yu, C.; Qiu, J.S.

    2009-12-15

    Carbon-encapsulated magnetic nanoparticles (CEMNs) were fabricated on a large scale by arc-plasma assisted CVD in acetylene. The coal-derived metal-containing (Fe, Co and Ni) carbon rods were used as anodes, while a high-purity graphite rod was used as a cathode that remained unchanged during the arcing process. The CEMNs obtained were characterized by TEM, XRD, Raman spectroscopy, N{sub 2} adsorption isotherms and VSM. The diameter distribution of the obtained CEMNs varies from 10 to 70 nm, of which the metal cores are proximately 5-50 nm. The core phases in Fe ) nanoparticles are body-centered cubic Fe and orthorhombic Fe3C while Co ) nanoparticles and Ni ) nanoparticles show the characteristic of a face-centered cubic structure. The Fe ), Co ) and Ni ) nanoparticles with well-ordered graphitic shells have the surface area of 89 m{sup 2}/g, 72 m{sup 2}/g and 75 m{sup 2}/g, respectively. The CEMNs show ferromagnetic of which was characterized by a ratio of remnant magnetization (MR) to saturation magnetization (MS).

  13. Spectroscopic of atmospheric pressure air jet plasma in transverses arc discharge

    E-Print Network [OSTI]

    Chernyak, V; Yukhimenko, V; Chernyak, Valeriy; Naumov, Vadym; Yukhimenko, Vitaliy

    2004-01-01

    Spectroscopic characterization of a specific case of the atmospheric pressure air jet plasma in the transverse cw dc arc discharge of high voltage was done. Within the spectrum of wavelengths from 200 to 1100 nm all remarkable emissions were monitored, and all excited atomic lines of N, O, H and molecular bands of NO, N2, O2, OH, CO, CN were identified. Using relative intensities of analytical CuI lines 510.5, 515.3, 521.8 nm (the product of electrode emission) and N2 2+ -system band at 337.1 nm (the dominating component of plasma-forming gas), the temperature of electronic excitation of free atoms, Texc, and the temperatures of excitation of vibrational and rotational states of molecules, TV and TR, were determined. It was found that there is no local LTE in this arc discharge air plasma during its space/time evolution, and effects of strong non-izothermality have a place in this case.

  14. Planning and Delivery of the Fully Dynamic Trajectory Modulated Arc Therapy: Application to Accelerated Partial Breast Irradiation

    E-Print Network [OSTI]

    Kay, Mark A.

    to Accelerated Partial Breast Irradiation J Liang1*, T Atwood1, B Fahimian1, E Chin1, K Otto2, D Hristov1, (1 partial breast irradiation (APBI) in a prone position. Methods: The TMAT algorithm was built on VMAT. TMAT delivery was implemented on Varian TrueBeamTM STx via XML scripts. 10 prone breast irradiation

  15. Influence of Fe-doped Graphite Electrode Characteristics on Ar-H2 Carbon Arc Plasma and SWCNT Formation

    SciTech Connect (OSTI)

    Huczko, A.; Lange, H.; Bystrzejewski, M.; Ando, Y.; Zhao, X.; Inoue, S.

    2005-09-27

    Two Fe-doped (ca. 1 at.%) homogeneous graphite electrodes (different graphite microcrystals, degree of graphitization and, thereby, electrical conductivities) electrodes were used in the process of production of single-walled carbon nanotubes in Ar-H2 arc plasma under pressure 26 kPa. The C2 content (namely carbon vapor pressure) and temperature distributions in the arc plasma were determined using optical emission spectroscopy. The mechanism of CNT formation based on carbon dimers as the building blocks seems to be at least questionable.

  16. Contrib. Plasma Phys. 51, No. 2-3, 293 296 (2011) / DOI 10.1002/ctpp.201000061 LTE Experimental Validation in a Gas Metal Arc Welding Plasma

    E-Print Network [OSTI]

    2011-01-01

    Validation in a Gas Metal Arc Welding Plasma Column F. Valensi1,2 , S. Pellerin1 , A. Boutaghane3 , K, France 7 CTAS-Air Liquide Welding, Saint Ouen l'Aum^one, 95315 Cergy-Pontoise cedex, France Received 12 Spectroscopy, Boltzmann Plot, Sola method, LTE. During gas metal arc welding (GMAW), the plasma obtained has

  17. An innovative high-power constant-current pulsed-arc power-supply for a high-density pulsed-arc-plasma ion-source using a LaB{sub 6}-filament

    SciTech Connect (OSTI)

    Ueno, A.; Oguri, H.; Ikegami, K.; Namekawa, Y.; Ohkoshi, K.; Tokuchi, A.

    2010-02-15

    An innovative high-power constant-current (CC) pulsed-arc (PA) power-supply (PS) indispensable for a high-density PA plasma ion-source using a lanthanum hexaboride (LaB{sub 6}) filament was devised by combining a constant-voltage (CV) PA-PS, which is composed of an insulated gate bipolar transistor (IGBT) switch, a CV direct-current (dc) PS and a 270 mF capacitor with a CC-PA-PS, which is composed of an IGBT-switch, a CC-dc-PS and a 400 {mu}H inductor, through the inductor. The hybrid-CC-PA-PS succeeded in producing a flat arc-pulse with a peak power of 56 kW (400 Ax140 V) and a duty factor of more than 1.5%(600 {mu}sx25 Hz) for Japan Proton Accelerator Research Complex (J-PARC) H{sup -} ion-source stably. It also succeeded in shortening the 99% rising-time of the arc-pulse-current to about 20 {mu}s and tilting up or down the arc-pulse-current arbitrarily and almost linearly by changing the setting voltage of its CV-dc-PS.

  18. SU-E-T-508: End to End Testing of a Prototype Eclipse Module for Planning Modulated Arc Therapy On the Siemens Platform

    SciTech Connect (OSTI)

    Huang, L [Huntsman Cancer Hospital, Salt Lake City, UT (United States); Sarkar, V [University of Utah Hospitals, Salt Lake City, UT (United States); Spiessens, S [Varian Medical Systems France, Buc Cedex (France); Rassiah-Szegedi, P; Huang, Y; Salter, B [University Utah, Salt Lake City, UT (United States); Zhao, H [University of Utah, Salt Lake City, UT (United States); Szegedi, M [Huntsman Cancer Hospital, The University of Utah, Salt Lake City, UT (United States)

    2014-06-01

    Purpose: The latest clinical implementation of the Siemens Artiste linac allows for delivery of modulated arcs (mARC) using full-field flattening filter free (FFF) photon beams. The maximum doserate of 2000 MU/min is well suited for high dose treatments such as SBRT. We tested and report on the performance of a prototype Eclipse TPS module supporting mARC capability on the Artiste platform. Method: our spine SBRT patients originally treated with 12/13 field static-gantry IMRT (SGIMRT) were chosen for this study. These plans were designed to satisfy RTOG0631 guidelines with a prescription of 16Gy in a single fraction. The cases were re-planned as mARC plans in the prototype Eclipse module using the 7MV FFF beam and required to satisfy RTOG0631 requirements. All plans were transferred from Eclipse, delivered on a Siemens Artiste linac and dose-validated using the Delta4 system. Results: All treatment plans were straightforwardly developed, in timely fashion, without challenge or inefficiency using the prototype module. Due to the limited number of segments in a single arc, mARC plans required 2-3 full arcs to yield plan quality comparable to SGIMRT plans containing over 250 total segments. The average (3%/3mm) gamma pass-rate for all arcs was 98.5±1.1%, thus demonstrating both excellent dose prediction by the AAA dose algorithm and excellent delivery fidelity. Mean delivery times for the mARC plans(10.5±1.7min) were 50-70% lower than the SGIMRT plans(26±2min), with both delivered at 2000 MU/min. Conclusion: A prototype Eclipse module capable of planning for Burst Mode modulated arc delivery on the Artiste platform has been tested and found to perform efficiently and accurately for treatment plan development and delivered-dose prediction. Further investigation of more treatment sites is being carried out and data will be presented.

  19. 10/19/10 8:28 PM38320 -Create an ArcGIS.com Web map using URL parameters Page 1 of 2http://resources.arcgis.com/content/kbase?fa=articleShow&d=38320

    E-Print Network [OSTI]

    Wright, Dawn Jeannine

    10/19/10 8:28 PM38320 - Create an ArcGIS.com Web map using URL parameters Page 1 of 2http:28 PM38320 - Create an ArcGIS.com Web map using URL parameters Page 2 of 2http://resources.arcgis.com/content/kbase?fa=articleShow&d=38320 HowTo: Create an ArcGIS.com Web map using URL parameters Article ID: 38320 Software: ArcGIS Online

  20. A Kinematic Approach To Assessing Environmental Effects: Star-Forming Galaxies in a z~0.9 SpARCS cluster using Spitzer 24um Observations

    E-Print Network [OSTI]

    Noble, A G; Muzzin, A; Wilson, G; Yee, H K C; van der Burg, R F J

    2013-01-01

    We present an infrared study of a z=0.872 cluster, SpARCS J161314+564930, with the primary aim of distinguishing the dynamical histories of spectroscopically confirmed star-forming members to assess the role of cluster environment. We utilize deep MIPS imaging and a mass-limited sample of 85 spectroscopic members to identify 16 24um-bright sources within the cluster, and measure their 24um star formation rates (SFRs) down to ~6 Msolar/year. Based on their line-of-sight velocities and stellar ages, MIPS cluster members appear to be an infalling population that was recently accreted from the field with minimal environmental dependency on their star formation. However, we identify a double-sequenced distribution of star-forming galaxies amongst the members, with one branch exhibiting declining specific SFRs with mass. The members along this sub-main sequence contain spectral features suggestive of passive galaxies. Using caustic diagrams, we kinematically identify these galaxies as a virialized and/or backsplash...

  1. Exhaust gas fuel reforming of Diesel fuel by non-thermal arc discharge for NOx trap regeneration

    E-Print Network [OSTI]

    Boyer, Edmond

    , coming into force in September 2014, set a 56 % reduction of NOx emissions compared to Euro stage V (80 trap technology, also called NOx Storage and Reduction (NSR), was first developed by Toyota in 199411 Exhaust gas fuel reforming of Diesel fuel by non- thermal arc discharge for NOx trap regeneration

  2. ARC: A compact, high-field, fusion nuclear science facility and demonstration power plant with demountable magnets

    E-Print Network [OSTI]

    Sorbom, B N; Palmer, T R; Mangiarotti, F J; Sierchio, J M; Bonoli, P; Kasten, C; Sutherland, D A; Barnard, H S; Haakonsen, C B; Goh, J; Sung, C; Whyte, D G

    2014-01-01

    The affordable, robust, compact (ARC) reactor conceptual design study aims to reduce the size, cost, and complexity of a combined fusion nuclear science facility (FNSF) and demonstration fusion Pilot power plant. ARC is a 270 MWe tokamak reactor with a major radius of 3.3 m, a minor radius of 1.1 m, and an on-axis magnetic field of 9.2 T. ARC has rare earth barium copper oxide (REBCO) superconducting toroidal field coils, which have joints to enable disassembly. This allows the vacuum vessel to be replaced quickly, mitigating first wall survivability concerns, and permits a single device to test many vacuum vessel designs and divertor materials. The design point has a plasma fusion gain of Q_p~13.6, yet is fully non-inductive, with a modest bootstrap fraction of only ~63%. Thus ARC offers a high power gain with relatively large external control of the current profile. This highly attractive combination is enabled by the ~23 T peak field on coil with newly available REBCO superconductor technology. External cu...

  3. Ballistic-Failure Mechanisms in Gas Metal Arc Welds of Mil A46100 Armor-Grade Steel: A Computational

    E-Print Network [OSTI]

    Grujicic, Mica

    -welding of a prototypical high-hardness armor-grade martensitic steel, MIL A46100. The model predictions concerning-tempered, high-hardness, low-alloy martensitic, ar- mor-grade steel). A summary of Johnson-Cook material- modelBallistic-Failure Mechanisms in Gas Metal Arc Welds of Mil A46100 Armor-Grade Steel

  4. Multiphysics Modeling and Simulations of Mil A46100 Armor-Grade Martensitic Steel Gas Metal Arc Welding

    E-Print Network [OSTI]

    Grujicic, Mica

    Multiphysics Modeling and Simulations of Mil A46100 Armor-Grade Martensitic Steel Gas Metal Arc-welding of MIL A46100, a prototypical high-hardness armor martensitic steel. The model consists of five distinct) of a prototypical high-hardness armor-grade martensitic steel MIL A46100 (Ref 1). It is hoped that the availability

  5. 1358 IEEE TRANSACTIONS ON MAGNETICS, VOL. 40, NO. 2, MARCH 2004 Eddy-Current Effects in Circuit Breakers During Arc

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1358 IEEE TRANSACTIONS ON MAGNETICS, VOL. 40, NO. 2, MARCH 2004 Eddy-Current Effects in Circuit Abstract--This paper deals with the modeling of eddy currents generated by arc motion during opening phases in determining eddy currents in splitter plates, the second one is devoted to the calculation of eddy currents

  6. Theoretical study of Diesel fuel reforming by a non-thermal arc discharge A. Lebouvier1,2

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Theoretical study of Diesel fuel reforming by a non-thermal arc discharge A. Lebouvier1,2 , G anti-pollution norm namely for Diesel powered vehicles. NOx (NO, NO2,...) are very irritant pollutants- nologies purge is the use of non-thermal plasma. Plasma reforming of diesel fuel and exhaust gas mix- ture

  7. Generation of high charge state metal ion beams by electron cyclotron resonance heating of vacuum arc plasma in cusp trap

    SciTech Connect (OSTI)

    Nikolaev, A. G.; Savkin, K. P.; Oks, E. M.; Vizir, A. V.; Yushkov, G. Yu.; Vodopyanov, A. V.; Izotov, I. V.; Mansfeld, D. A.

    2012-02-15

    A method for generating high charge state heavy metal ion beams based on high power microwave heating of vacuum arc plasma confined in a magnetic trap under electron cyclotron resonance conditions has been developed. A feature of the work described here is the use of a cusp magnetic field with inherent ''minimum-B'' structure as the confinement geometry, as opposed to a simple mirror device as we have reported on previously. The cusp configuration has been successfully used for microwave heating of gas discharge plasma and extraction from the plasma of highly charged, high current, gaseous ion beams. Now we use the trap for heavy metal ion beam generation. Two different approaches were used for injecting the vacuum arc metal plasma into the trap - axial injection from a miniature arc source located on-axis near the microwave window, and radial injection from sources mounted radially at the midplane of the trap. Here, we describe preliminary results of heating vacuum arc plasma in a cusp magnetic trap by pulsed (400 {mu}s) high power (up to 100 kW) microwave radiation at 37.5 GHz for the generation of highly charged heavy metal ion beams.

  8. Tuesday, July 14th, 2009 Advances in GIScience: Research Session 2 A Customization of the Arc Marine

    E-Print Network [OSTI]

    Wright, Dawn Jeannine

    Advances in GIScience: Research Session 2 Foundation data types: 0:20/0:50 #12;Tuesday, July 14th, 2009Tuesday, July 14th, 2009 Advances in GIScience: Research Session 2 A Customization of the Arc State University Title Slide: 0:00/0:00 #12;2 Tuesday, July 14th, 2009 Advances in GIScience: Research

  9. METAL TRANSFER CONTROL IN GAS METAL ARC WELDING L.A. Jones, T.W. Eagar, J.H. Lang

    E-Print Network [OSTI]

    Eagar, Thomas W.

    controls both the metal transfer process and the base-plate heating process. It would be advantageousMETAL TRANSFER CONTROL IN GAS METAL ARC WELDING L.A. Jones, T.W. Eagar, J.H. Lang Massachusetts, precision current control, and flexible real-time computer control is described. 1 Introduction Gas metal

  10. Mouvements actuels des blocs tectoniques dans l'arc Btico-Rifain partir des mesures GPS entre 1999 et 2005

    E-Print Network [OSTI]

    Demouchy, Sylvie

    GPS entre 1999 et 2005 Abdelilah Tahayt a,b , Taoufik Mourabit a,1 , Alexis Rigo b,*, Kurt L. Feigl b (2008). # 2007 Académie des sciences. Publié par Elsevier Masson SAS. Tous droits réservés. Abstract Present-day movements of tectonic blocks in the Betic­Rif Arc from GPS measurements 1999­2005. GPS

  11. STERN AND BLOOMER Figure 1. Tectonic and physiographic map of the Philippine Sea, Mariana Arc, and sur-

    E-Print Network [OSTI]

    Stern, Robert J.

    #12;STERN AND BLOOMER Figure 1. Tectonic and physiographic map of the Philippine Sea, Mariana Arc was composed of trapped oceanic crust. They noted that the magnetic anomalies of the West Philippine Basin with the spreadingdirection identified for the West Philippine Basin (Hilde and Lee, 1984).Second, the oldest crust, every

  12. sedimentation under permanent ice cover in the Arc-tic Ocean. Cont. Shelf Res. 14: 279-293.

    E-Print Network [OSTI]

    390 Notes sedimentation under permanent ice cover in the Arc- tic Ocean. Cont. Shelf Res. 14: 279-293. HAWLEY, N. 1988. Flow in cylindrical sediment traps. J. Great Lakes Res. 14: 76-88. HOLM-HANSEN, O., C. J. Effectiveness of various treatments in retarding mi- crobial activity in sediment trap material

  13. Magnetic lineations constraints for the back-arc opening of the Late Neogene South Banda Basin (eastern Indonesia)

    E-Print Network [OSTI]

    Dyment, Jérôme

    Magnetic lineations constraints for the back-arc opening of the Late Neogene South Banda Basin Laboratoire de PeÃ?trologie, Tour 26-16, BoIÃ?te 110, UniversiteÃ? Paris VI, 4 place Jussieu, 75252 Paris Cedex The South Banda Basin is located within eastern Indonesia near the triple junction between the Eurasian

  14. Characterization of Gas Metal Arc Welding welds obtained with new high Cr-Mo ferritic stainless steel filler wires

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    for homogeneous welding, by Gas Metal Arc Welding (GMAW) process, of a modified AISI 444 ferritic stainless steel, of the K44X assemblies are excellent. Keywords: ferritic stainless steel, welding, oxidation, tensile test of massive components, manifolds can now be made of stainless steel, using tubes or thin sheets rolled

  15. Precipitation of auroral protons in detached arcs Thomas J. Immel, Stephen B. Mende, Harald U. Frey, Laura M. Peticolas,

    E-Print Network [OSTI]

    California at Berkeley, University of

    Precipitation of auroral protons in detached arcs Thomas J. Immel, Stephen B. Mende, Harald U. Frey of particle precipitation at sub-auroral latitudes on the dayside. The signature of this precipitation is seen conjunction with the FAST satellite demonstrates the presence of precipitating protons and the notable absence

  16. Inversion of a new circular-arc Radon transform for Compton scattering tomography This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-Print Network [OSTI]

    Nguyen-Verger, Maï K.

    Inversion of a new circular-arc Radon transform for Compton scattering tomography This article has:10.1088/0266-5611/26/6/065005 Inversion of a new circular-arc Radon transform for Compton scattering-arc Radon transform arising from the mathematical modeling of image formation in a new modality of Compton

  17. SU-E-T-631: Commissioning and Comprehensive Evaluation of the ArcCHECK Cylindrical Diode Array for VMAT QA

    SciTech Connect (OSTI)

    Chaswal, V; Weldon, M; Gupta, N; Rong, Y

    2014-06-15

    Purpose: Commissioning and comprehensive evaluation of ArcCHECK phantom for dosimetry of VMAT QA, using 6MV photon beam with and without the flattening filter. Methods: ArcCHECK was evaluated for response dependency on linac dose rate, instantaneous dose rate, radiation field size, beam angle and couch insertion. Scatter dose characterization, consistency and symmetry of response, dosimetric accuracy of fixed aperture arcs and clinical VMAT plans were investigated. Measurements were done using TrueBeam™ STx accelerator (Console version 1.6) with a 6 MV beam with and without flattening filter. Reference dose-grids were calculated using Eclipse TPS Analytical Anisotropic Algorithm (AAA version 10.0.39). Planned doses were calculated using symmetric 2mm 3D dose grids with 4 degree angular resolution defaulted to each control point. Gamma evaluations were performed in absolute dose mode, with default normalization to maximum dose in the curved plane and a low dose threshold of 10% to restrict the analysis to clinically relevant areas. Global and local gamma indices at 3mm/3% and 2mm/2% level were computed using SNC software (version 6.0). Results: Results of gamma analysis demonstrated an overall agreement between ArcCHECK measured and TPS calculated reference doses. Field size dependency was within 0.5% of the reference. Dose-rate based dependency was well within 1% of the TPS reference and the angular dependency was ±3% of the reference, as tested for BEV angles. At the level of 3%/3mm, narrow and wide open arcs as well as clinical VMAT cases demonstrated high level of dosimetry accuracy in global gamma passing rates for both 6X and 6F beams. At the level of 2%/2mm two VMAT cases involving the narrow heavily modulated arcs demonstrated lower passing rates. Conclusion: ArcCHECK phantom with latest software and hardware upgrades is suitable for VMAT QA. For higher sensitivity of 2%/2mm gamma analysis, we intend to use it as one of the VMAT QA evaluation metrics.

  18. Causal Factors of Weld Porosity in Gas Tungsten Arc Welding of Powder Metallurgy Produced Titanium Alloys

    SciTech Connect (OSTI)

    Muth, Thomas R [ORNL; Yamamoto, Yukinori [ORNL; Frederick, David Alan [ORNL; Contescu, Cristian I [ORNL; Chen, Wei [ORNL; Lim, Yong Chae [ORNL; Peter, William H [ORNL; Feng, Zhili [ORNL

    2013-01-01

    ORNL undertook an investigation using gas tungsten arc (GTA) welding on consolidated powder metallurgy (PM) titanium (Ti) plate, to identify the causal factors behind observed porosity in fusion welding. Tramp element compounds of sodium and magnesium, residual from the metallothermic reduction of titanium chloride used to produce the titanium, were remnant in the starting powder and were identified as gas forming species. PM-titanium made from revert scrap where sodium and magnesium were absent, showed fusion weld porosity, although to a lesser degree. We show that porosity was attributable to hydrogen from adsorbed water on the surface of the powders prior to consolidation. The removal / minimization of both adsorbed water on the surface of titanium powder and the residues from the reduction process prior to consolidation of titanium powders, are critical to achieve equivalent fusion welding success similar to that seen in wrought titanium produced via the Kroll process.

  19. CSR induced microbunching gain estimation including transient effects in transport and recirculation arcs

    SciTech Connect (OSTI)

    Tsai, Cheng; Douglas, David R.; Li, Rui

    2015-09-01

    The coherent synchrotron radiation (CSR) of a high brightness electron beam traversing a series of dipoles, such as transport or recirculation arcs, may result in the microbunching instability (?BI). To accurately quantify the direct consequence of this effect, we further extend our previously developed semi-analytical Vlasov solver to include more relevant coherent radiation models than the steady-state free-space CSR impedance, such as the entrance and exit transient effects derived from upstream beam entering to and exiting from individual dipoles. The resultant microbunching gain functions and spectra for our example lattices are presented and compared with particle tracking simulation. Some underlying physics with inclusion of these effects are also discussed.

  20. Realistic simulations of gravitational lensing by galaxy clusters: extracting arc parameters from mock DUNE images

    E-Print Network [OSTI]

    Meneghetti, Massimo; Grazian, Andrea; De Lucia, Gabriella; Dolag, Klaus; Bartelmann, Matthias; Heymans, Catherine; Moscardini, Lauro; Radovich, Mario

    2007-01-01

    We present a newly developed code that allows simulations of optical observations of galaxy fields with a variety of instruments. The code incorporates gravitational lensing effects and is targetted at simulating lensing by galaxy clusters. Our goal is to create the tools required for comparing theoretical expectations with observations to obtain a better understanding of how observational noise affects lensing applications such as mass estimates, studies on the internal properties of galaxy clusters and arc statistics. Starting from a set of input parameters, characterizing both the instruments and the observational conditions, the simulator provides a virtual observation of a patch of the sky. It includes several sources of noise such as photon-noise, sky background, seeing, and instrumental noise. Ray-tracing through simulated mass distributions accounts for gravitational lensing. Source morphologies are realistically simulated based on shapelet decompositions of galaxy images retrieved from the GOODS-ACS ...